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Friday, February 20, 2009

Throttle Position Sensor





The top two photos are of a Throttle Position Sensor off a 2005 Ford Expedition with 5.4L Engine. The TPS acting up will cause a variety of goofy driving problems, including sticking you on the roadside.
A repair which has cropped up lately in the last couple months on the 5.4 Liter Ford engine is a faulty Throttle Position Sensor. The latest one yesterday was a 2005 Ford Expedition with only 31,000 miles on it. They all had relatively low mileage, between 30,000 and 60,000 miles. The symptoms were relatively the same: no power on the freeway, surging RPM’s, and check engine light on with various throttle position sensor codes. I’m writing this up because when I see something like Throttle Position Sensors acting up on similar applications in a short period of time, it may mean a pattern failure, where I will be seeing more. The pictures above show what a Throttle Position Sensor looks like and where it’s mounted. When the gas pedal is pushed down to accelerate the vehicle, the TPS feeds throttle position electrically to the onboard computer. I included a different view of the plastic intake on the Expedition’s engine.

Tune-ups on these 5.4L Engines can be very expensive. They have a built in problem in that when the spark plugs are removed, they many times strip the threads out of the head. Techs try to avoid this by spraying WD-40 into the spark plug hole at a depth so it pools around the plug base. Loosening the plug a quarter turn at a time and tightening it occasionally while letting it soak in the WD-40 in between helps.

01/12/12 - With so many comments on this post, I decided to add an addendum to it covering some of the further items afflicting the Expedition. Here’s a list of some things I’ve experienced with these.
1.                  If you have multiple throttle codes, it will almost always mean an electronic throttle body replacement along with the throttle position sensor.
2.                  The wiring harness running behind the Exhaust Gas Recirculation tube chaffs through the harness wiring and causes a multitude of goofy sensor and code problems.
3.                  They have updated spark plugs for these. In a related note, misfiring coils and spark plugs also cause an array of unrelated codes. My advice is change both the spark plugs and individual coil on plug assemblies every 60,000 miles.
4.                  The alternator going out on the Expeditions can and does cause electronic interference, disrupting engine and transmission operation.
5.                  A link to the Technical Service Bulletin for Transmission and Drivability problems related to a check ball breaking inside the transmission valve body.
6.                  I came across myriad problems in the East and Midwest after much research where a leaking windshield leaks water into the fuse box. The fuel pump relay is built into it so the fuse box has to be replaced when leakage is found. If the C270 dark green wire at the fuse box has no power it would point to corrosion in the fuse box. That could also cause myriad weird other electrical problems.
That’s all for this update, but if you’re appreciative of the information, here is a link to my new novel COLD BLOODED for Nook and Kindle. If you’re kind enough to read it and like it, please review it on the site you purchase it from. Thank You! Every little bit helps my writing gig. :)

535 comments:

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Anonymous said...

hello bernard,
i have a 2001 ford f250 5.4l that has intermittant starting, but idles fine when it does run.then, when i stomp on the gas, there is no immediate power and the rpm,s go up then down a little bit, then back up. no codes show up, had a rebuilt tranny, and tune up 30000 miles ago, and the fuel pressure is within specs. diagnostic guy is scratching his head as well. would it be a tps? the truck has 147000 miles on it. thanks alot,
seanboy

BernardL said...

Seanboy, I can give you some possibilities. Yes, the TPS can do what you're experiencing without setting a code. If your diagnostic guy has something more than a code checker, he should look at the mode 6 data for small misfires and sensor codes not setting a main computer code. If there are any misfire hints in the mode 6 data, replace all the COP's (Coil On Plug assemblies). Also Ford has had trouble with the DPFE (Differential Pressure Feedback EGR) sensor that will cut out other sensors. It too might show up in the mode 6 data. Plugged catalytic converters is another possibility if your mechanic hasn't done a back pressure test yet. I assume vacuum leaks have already been checked?

Anonymous said...

bernard,
thanks for the info. i will let the diagnostic guy know to check mode 6 out, and do a back pressure check as well. thanks alot for the tips and i will let ya know how it turns out.
seanboy

BernardL said...

My novel Cold Blooded is now on Nook too.

COLD BLOODED on Nook

frank said...

hey bernard happy thanksgiven,do you know if the brake calipers on ford escape are metric , cant find size need to chane rotors .thanks frank in nys

BernardL said...

Happy Thanksgiving, Frank. I'm not aware of any problems on finding parts for the Escape. Anything that new will be metric. One of the best on-line parts places carrying just about everything imaginable is here: RockAuto.com

KevPar said...

Bernard: Can an intermittent loss of connection to the positive battery terminal cause by a cracked terminal connection cause my 03 Ford f150 to stall suddenly? Working through all of the suggestions and discovered this while planning to remove the power chip... Thank you for your time

BernardL said...

KevPar, most definitely! Any interruption of power or ground will shut the vehicle off, especially at the battery terminal.

Unknown said...

Hi Bernard, I have a 2005 expedition and just pulled the codes P2104 and P2114. The car stalled on me while stopping for a red light. Had trouble restarting, but finally started and I drove about 1/2 mile. Stalled again and this time the check engine soon light appeared. Was able to drive all the way home with no problems, but light remains on. Any thoughts of a repair. Just had the transmission completely rebuilt at 77,000. Could these be related to eachother?? Thanks Stephanie

Mike said...

Hi Bernard. I just came across your blog after a couple days of google searching my problem. I have a 05 F150 5.4, which is dropping RPM's and is stalling when I am parking either in reverse or drive. The RPM's drop to the 300 range and the whole truck shudders and the engine either stalls or I put it in Neutral and rev it back up before it has a chance. This problem just started about 3 days ago. A couple of people have suggested the TPS and it seems like it may be the case, just wanted to get your opinion?

THANKS

BernardL said...

Stephanie, on your 2005 those dual codes usually mean you will have to change the Electronic Throttle Body.

Mike, you probably have the same problem Stephanie has with needing a new Electronic Throttle Body, but you didn't state whether you had any codes to go by. Remember, I don't know your vehicle. If you've had intermittent misfires, cheapest Rotten Robbie fuel you could find, and very little maintenance done, your problem could be dirty fuel injectors, plugged catalytic converters, bad plugs and 'coil on plug assemblies'. Although this TSB is related to shifting, I've had it also be related to stalling because the vehicle remains in converter lock-up as the vehicle stops.
http://ww2.justanswer.com/uploads/bobover/2010-01-23_231853_percievedlackofpower1-2f150.pdf

Mike said...

Thanks, Bernard. It isn't throwing any codes and I have had no other problems. I replaced the fuel filter, plugs and MAF about 2 months ago. I did forget to mention that the first stall happened a day after I towed my boat for the winter. Drove fine, no issues during the tow and back home, but stalled the next day when I was backing into a parking spot. It has only happened a few times since, but this morning it did when I was in drive pulling into a spot after about 45 mins of driving.

BernardL said...

Mike, you may very well have a transmission problem, but a shudder and stall can be related to a misfire too. If you've never replaced the 'Coil on Plug' assemblies, they may be causing a misfire the usual code read isn't picking up. You need a more in depth computer diagnostic with a scanner that can read 'Mode 6' data to determine if you have a transmission or misfire problem. The 'Mode 6' data may reveal something else related to the throttle control too. I don't like coincidences, like pulling a trailer, and it may be that was the last straw for your tranny.

Stewart196 said...

I changed out the TPS on my 99 expedition 5.4 2wd and all was going well until I encountered a new problem that has me stumped. My fuel gauge is not working right. I changed the fuel pump / sending unit twice and it still reads 1/4 in the dash panel and the overhead digital display. Before this wouldn't read at first but after about 5 minutes of running time it would show me what I had in the tank. I've been all over the web and have yet to find any useful information on this so needless to say I'm at my whits end. Is there a relay or could there be a short inline? Like I said, truck runs great I just have no idea when it will leave me stuck on the side of the road. Thank you in advance for any help.

BernardL said...

Stewart, I can only give you some suggestions. Most problems like yours have to do with connectors, usually at the tank. A corroded contact or ground will void the signal. The easy way is to have a manual hook up at the tank which most shops do to vary the signal and check to see if gauge then works correctly. If it does, then you know something's not right at the tank. If the gauge still doesn't work, then you know either the cluster or computer has a problem or a wire is open somewhere in between. I'm sorry, but electrical problems are not magic. Most are tedious wire tracing of powers and grounds. You didn't mention if you replaced the tank unit with a Ford OEM unit. If you didn't, that would be my first suspect.

Anonymous said...

Thanks for your Blog Bernard- I have learned much about my 2005 2wd XLT Expedition from you. Mine has been a good steed to me since new in 2005. Recently, I have noticed a driveline 'bump' when I am at 40-50 mph and slowly accelerating (accelerating without upshifting). At 40mph, I hold the speed then accellerate to 45mph slowly and the bumping begins- it is a bucking actually- not loss of power (engine) bucking, but either tranny or rear end. It has progressed in the past 5k miles. The car has 93k miles and the engine oil has been done every 4k, tranny every 10k (yes, I'm anal, rear-end every 20k-30k miles. Is this a known thing? Is this pointing more toward a rear-end issue or tranny? Thanks- Casey McCann, Costa Mesa

BernardL said...

Casey, you may have missed this TSB mentioned a few times in the comments. It concerns a similar problem on those 2005's.

http://ww2.justanswer.com/uploads/bobover/2010-01-23_231853_percievedlackofpower1-2f150.pdf

Jeff said...

Hey bernard,I have a good one for you...2005 f-150 xlt 4x4, 5.4l. I have a P0308, cylinder 8 miss. it misses only under load. i could baby the truck around town with no cel. accelerating without downshifting out of overdrive, it starts to miss, and misses HARD. shakes the whole truck violently. same thing on the freeway, once up to cruising speed(65mph) punch the throttle to pass, and it falls flat on its face, feels like an entire bank shut down and has a more violent shake. let out the throttle, computer figures it out, then stops. ??? i know there's a miss.. this is more than dropping just a cylinder.no tps codes.BUT I plug into the truck and monitor everything. with the gas pedal mashed... TPS = 76.1% FP = 38.3psi Rel TPS 64.3% TPS B(?)= 91% ACC Pedal D =83.9% ACC Pedal E = 80% ...F = 69% command tac 100%... please tell me it wouldn't have anything to do with the vct acting up... thank you very much in advance. Im kinda new to the modular engine game, as i have had zero problems in 127k miles.

BernardL said...

Jeff, you didn't say anything about what you've done to find the P308 misfire code. Have you made sure of good compression in that cylinder. Have you replaced all the spark plugs with updated ones and replaced all the Coil On Plug assemblies at any time. Your fuel pressure is a bit low. You'll also need to check exhaust back pressure to eliminate plugged catalytic converters. Bad gas and plugged fuel injectors can also cause the shaking and misfires. You really need to do some in depth diagnostics.

Roselyn Neeley said...

Hi Bernard it is Roselyn Again I am having the same high RPM trouble so I Had it put on a computer and it said these things are wrong with it ......Air intake and Ignition coil and misfire on Cylinder 7 which is a spark plug....by the way this is a 2000 ford expedition it drives good at times and then when u park it a hour or 2 an start drivin the rpm's go up to 5-6000 and u got to hold the break down to keep it from shooting off down the road and shut it right off and sit it for 10 minutes and start again and its back to normal like nothing happpened .....are those 3 things the computer named could they be the reason the rpm's keep shooting up ???? i plan on having those 3 the computer says fixed tomarrow but i am trying to see if those 3 things are the reason my rpm's are acting out

BernardL said...

Roselyn, you don't mention any specific code, or what exactly the shop is replacing, so I have no idea what the computer is pointing out. Yes, intake manifold leaks can cause high RPM. If you've never had the spark plugs changed or the Coil On Plug assemblies yet, those should all be changed.

Anonymous said...

hi bernard, i was wondering if you have any idea what voltage an o2 sensor will be reading if its sniffing rich exhaust??

BernardL said...

The richer the exhaust, the lower the voltage reading from the oxygen sensor. They normally vary from just below .2 to just above .8 volts. If the sensor in front of the catalytic converter is reading steadily on the low end it means the system is running rich and the sensor is trying to get the computer to decrease fuel injector opening. If the catalytic converter is doing its job, the oxygen sensor after the cat will read in a steady upper level.

Roselyn said...

Ok i found out the problem to the very high rpm's while driving its the trottle position sensor and also its sticking because there was rust and stuff on there so we have to spray it down alot other then that the problem was found

Anonymous said...

hello. i have an 03 expedition 5.4L and my problem is when i start the car the o/d off light flashes then when i put it into gear the engine stalls.any suggestions? thanks.

BernardL said...

Thanks for the update, Roselyn.

Anon, I'd need a lot more diagnostic information than that. Have your vehicle checked out. Guessing at the problem can cost you a lot of money and not solve it. I do know if your Coil On Plug assemblies misfire they can cause unrelated codes and electrical impulses.

Anonymous said...

Thanks for all the help you provide to other people. Now I'm hoping you may be able to help me. Yesterday an employee said he removed the air filter in our 1998 F150 v6 work truck. He knocked the dust out of it and then reinstalled it. He said it was pretty dirty. Today he stated that the truck was running rough like a skip or shutter. I removed filter and truck ran smoother so I'll replace it tomorrow. this evening he stated that he thought the shutter maybe in the transmission which i believe because I felt a minor shutter in it a year ago after swapping in a new rebuilt motor. Don't have history of how it acted before rebuild because i bought it with bad motor. Ok so now i have a fault code of P0755. Do you think these are two separate issues or could the TPS cause this code? Could the TPS be damaged after maybe loosing dust in filter? I don't have any other codes. Was going to start with checking all tranny wire connection then replace the solenoid. Oh forgot!!! this is a weird one he said that when he shifted into drive the truck wanted to go in reverse until he stepped on brake then it went forward but sluggish.

BernardL said...

Anon, it doesn't matter. You're getting a shift solenoid code. You need to take the truck in for diagnosis.

Tyler said...

I have a 2005 F150 5.4, lately I was having problems with it I have a Edge Evolution programmer in it, dont ever use it except for looking at the temps of engine and for the diagnostics. Cant remember what the numbers are but the 2 Ive been reading have been Throttle actuator control system forced idle and tacs stuck closed. Ive already replaced TPS its aftermarket though, do you think this could be a vaulty sensor or should I just go with a hole new throttle body. Really dont know what else to do. keeps throwing those 2 codes....it will usually seem to run fine then other times it will just stay at idle no throttle response.

BernardL said...

Tyler, it does complicate things when you replace OEM with aftermarket AND have an add on programmer. When you get multiple throttle codes it nearly always means an electronic throttle body replacement. I've had reports you don't always get the OEM TPS with the throttle body. If you don't, make sure you put one on when you replace the throttle body.

Anonymous said...

Bernard,
I have read your blog with great interest. I have an 06 Navigator that is showing advance trac mode and fail safe.Barely runs. Dealer said ETB was bad, replaced and the next day the same thing occured.
I haven't seen any mention of these
displays concurrent with ETB
problems.
Thanks
Dave

BernardL said...

Anon, I have not seen an ETB cause what you're having happen, but I did have one that had a bad alternator that caused electronic interference which did turn on the light. The dealer you had the ETB replaced at needs to look at the advanced diagnostic 'Mode 6' scan data again and see what's happened since they replaced the ETB.

Anonymous said...

My 2006 F150 5.4L has had a weird hesitaion in the 2200 RPM range since 60K miles (now 72K) I replaced the TB TPS with one from Advanced Auto Parts for $52.00 (20% off online coupon price) and it feels like a new truck! I just cut open the old TPS sensor to see the "windshield wiper" potentiometer insided. Not sure how to post pics here.

BernardL said...

Not necessary, Anon. I'm glad it worked out for you. If you're really set on sharing the pictures, upload them to a site like Windows Skydrive and provide the link in the comments section. Thanks for the update.

Anonymous said...

Thank you so much for putting all this info out here. My F150 has been acting up and this page has helped me confirm some of the issues.

Mikey1994 said...

Hey Bernard,

I have a 2006 5.4 Expedition where the Fail Safe Mode message displayed, the engine stalled while my wife was driving. It threw a code of P2104. I replaced the TPS after reading your blog and several other posts - just to see if it fixed the problem. Five days later, she got the same message and the engine stalled again. It threw another P2104 code. So I am guessing it is the throttle body that needs to be replaced? Thanks in advance.

BernardL said...

Yeah, Mikey, on that one with the P2104 code again, the electronic throttle body would be the next step because of it being a pattern failure they're obviously having continued problems with.

Judd Bonham said...

Wife drove the 02 4.6L auto this morning and said that it jerked on her when trying to accelerate from a dead stop multiple times. Also, from a stop, it rolled backward on her as if in neutral when trying to accelerate into roadway. On highway when foot lifted from accelerator the rpm's jumped from 2k to 4-5000. Thanks for suggestions.

BernardL said...

Without data, Judd, I can't even guess. That it rolled back as if in neutral would point to a transmission failure, but in any case, you need to take it in for diagnosis.

Eddie Yang said...

Hi Bernard, firstly I would like to thank you for what you're doing, if you're in the NY area I'd definitely trust my cars in your garage. I own a '04 expedition EB and the problem I have is, when I'm stopped with the engine in drive, it sounds like the idle rpm is fluctuating slightly, but not enough to move the tach, the car doesn't stall like some of the people here are experiencing. I thought maybe it's the coolant and topped off the coolant but that didn't help. This started happening after i had done a full tune-up that included all new coil packs and spark plugs. There is no check engine error and unfortunately i don't have access to a computer to check for codes. Any bit of your knowledge is greatly appreciated, Thanks in advance

BernardL said...

It could be the first sign of the electronic throttle body giving you trouble, Eddie. Unfortunately, the only way to get a hint of what might be wrong is to take it in for a diagnostic check. You may have noticed in other comments I've made here that there is a lot more data that can be garnered from a scanner, including the in depth 'Mode 6' data. It can predict potential problem areas to some extent. Although you don't have a check engine light on, there may be a data set in memory.

Becky said...

Hi Bernard, I have a 2005 Lincoln Town Car that while driving at any speed, or even in reverse, will lose all power and stall. The service engine and wrench symbol light up. I put it in neutral and restart it. Service lights turn off and car runs fine. It is random. Have it at an auto electric shop. Code history shows TPS but mechanics do not think the symptoms fit that diagnosis. Any input?

BernardL said...

Becky, I'm not sure why the shop you have your vehicle in feels the symptoms don't match. They seem to match perfectly. Since you didn't post the exact codes, I can't tell you much more. If your vehicle set multiple TPS codes, I would be inclined to replace the Electronic Throttle Body as per the Ford Tech Service Bulletin.

Becky said...

Hi again - the codes in history are P2123, P2131, P2127, P2126

BernardL said...

Becky, those are not throttle position sensor codes. They are all Accelerator Pedal Position Sensor codes. I have only had to replace the Accelerator Assembly twice - both times due to damage not codes. I don't believe Ford sells the Accelerator Pedal Position Sensor separately. If I had to guess, I'd say the Electronic Throttle Body Assembly is causing the Acc. Pedal Pos. Sensor Codes. I'm not there so that's my best guess. If you've never had the Electronic Throttle Body Assembly changed, that would be what I'd do first if there's no visible damage to the Accelerator Pedal Position Sensor or Assembly in the cab.

Anonymous said...

Hi, I have similar problems to the ones posted about revving. I have 00 expo w/180K.On way back from NH (I live south of Boston, my rpms continued to get higher; pulled into driveway, put into park, and revved up to 2500 and stayed there. Friend sprayed WD40 on throttle cable a few days later and rpms went back to their normal 600 idle. That was 2 months ago and now it has started all over again. I sprayed WD40 on it and came back down briefly, but went back up to 2500 when I turned car back on. No check engine light came on either time. Any suggestions??

Rebekah and Holly said...

Bernard thanks for your help. I have a 06 Expedition XLT 5.4LEngine 4wd Truck keeps shutting off randomly at redlights, drive throughs, going down the inter state. Really no rhyme or reason as to when it happent. Check engine light came on and the computer pulled the TPS Code. Went and purchased the Sensor and it didn't fit. Any idea's as to why. It has been confirmed that it is the one for this truck and engine.

BernardL said...

Anon, there could be mode 6 data that could be detected at a shop with advanced scanner capability. My guess is if you haven't had the Electronic Throttle Body replaced yet, then it's a good bet that's what's wrong. Without data I can only guess.

R&H, my guess is you didn't purchase it from Ford with your VIN number and the number off the original sensor. If my guess is right, go purchase an OEM Ford sensor. It will fit.

Anonymous said...

Thanks Bernard - it's going in the shop tomorrow - if it is the electronic throttle, do you have a ball park for price? Just want to be prepared. Thanks for your help - you have a great site here.

BernardL said...

Anon, I'm sorry, but I don't quote prices. I hope you it works out well for you.

FRANK said...

HEY BERNARD HAVE PROBLEM 2003 ESCAPE GETTING CODE PO430[BANK 2],VEHICLE IS RUNNING GREAT COULD IT BE SENSORS,AND IF SO I CAN I TELL, BEFORE BUYINY FRONT CAT. REALLY NEED HELP THANKS FRANK IN NYS

BernardL said...

Frank, yes you need to have an in depth computer scan, including mode 6 data to determine for sure it’s not the oxygen sensors causing the PO430 code. Chances are it is the catalytic converter.

My advice is to change the oxygen sensors first anyway with OEM Ford sensors, front and rear if you’re going to guess. If they’re the originals, it’s a good idea anyway. If the code comes back, then you’ll have to change the front converter.

Feets said...

Bernard, I have a 2005 Expedition 4WD 5.4L like most on this thread. It has 127000 miles. Experienced the bucking at 40-45 mph. No codes. OHM'd the COPs and all the secondaries were way out of spec. Replaced all 8 COPs and all plugs. Fixed bucking problem. Then a few days later CEL came on and vehicle started to stall during stops. Can't remember all of the codes, but they referenced misfire in cylenders 2,3,4,and 8, engine running lean, bad catalytic converter, and crank shaft position sensor in bank 2. We figured it might be the sensor, so we replaced the sensor and cleared the codes. Fired up the vehicle and still have same stalling issues. CEL light came back on, this time with only a 506 code (i think) which referenced the IAC system. Took vehicle to shop and they are recommending replacing the entire throttle body, but they don't supply it. Have to get it from Ford. Have cleaned the fuel system, because yes we have used cheap gas often. Finally my question, should I think about replacing the sensor first and if that doesn't work, the entire throttle body or go ahead and replace the throttle body. I know I can get throttle body cleaner and remove the entire unit and clean it. Where should I start?

BernardL said...

Not in your case, Feets. Replace the electronic throttle body as the shop suggests.

Feets said...

Thanks Bernard.

I picked up a throttle body from Ford for $325. They did not have the gasket however. I did find a gasket at Autozone. Will this be ok? I know its just a $2 gasket, but wanted to be sure anyway and couldn't find a picture of it in my Haynes book.

BernardL said...

Feets, you just need to match it with the one you take off if you're unsure.

Anonymous said...

irv b

i have a 01 expediton xlt 4.6 motor. i have a rough idle . i have changed EGR valve IAP sensor , cleaned out throttle body replaced all gaskets, changed with used ones all the injectors and yes i cleaned them and used new o rings, replaced all cop and plugs i put new muffler on and still rough idle i am getting p0308 cylinder 8 misfire. i was told this was a common problem but was never told the solution to fix i have spent about 1000 bucks trying to figure this out and cant i need HELP. also if i reset the computer at some point it will blow white smoke out of tail pipe then it stops after a while and does not return. if anyone has had a problem like this and has got it fixed please let me know what you did. also did a compression check but i it was hard to get to and i could not get the adapter for it to screw in . so i used the other adapeter that you push in and hold while some one else crancks the motor i felt i was not a fair reading do to the lack of not being a seal tight in the cylinder please help ..

Bernard Lee DeLeo said...

Irv, first off, no you didn't clean the used injectors. You would have to have a pristine rebuilding shop to claim such a thing, so you very well might have a bad injector still. Enhanced scanner data would reveal a lot more info including fuel trims, and oxygen sensor data on each bank. If it's been missing for any length of time, it may have a partially plugged up catalytic converter. The left one plugs up first on those.

If you didn't use Motorcraft OEM COP's you may have a bad one on number 8.

The PCV hose rots on the back of the intake manifold which causes a vacuum leak that will show up as a miss on number 6 or 8 cylinder. It usually sets a lean code too.

A dirty fuel rail will dump fuel into #8 if you've been using cheap gas and running it on empty. Also, if you have a tendency to overfill the tank, they have a problem with the Evap Cannister filling with raw fuel, causing #8 cylinder to miss rich.

Lastly, unless you take it into a shop for actual testing of the compression how will you know if you don't simply have a burned valve? You can't guess at it and assume it's okay. If you have an old analog type vacuum gauge, hook it up to a manifold vacuum source and see what the needle does. If it oscillates you may have a broken valve spring.

If nothing obvious shows up, my advice is to quit throwing parts at it and get it checked out, starting with the basic of making sure you have good compression.

Anonymous said...

Bernard thanks . by meaning i cleaned the injectors i meant i let them soak in sea foam , also the 2 other things that i did was the pcv valve and hose the old one was pretty bad and the dpfe sensor. i went to pull the dpfe sensor off and the hose ripped in two pieces.thanks for your info i will get it checked and check out a few other things that you mentioned. i will get back to you shortly and let you know .thanks again Bernard

Anonymous said...

I just replaced my TPS in my '05 Expedition. I'm just about completely worthless with all things mechanical. Thanks for the tips and photos. Gave me the courage to give it a go. Oh yea, and it fixed all my weird lack of acceleration/engine revving issues. I pulled the old one off (factory as far as I know) and you could easily see why it wasn't working. The inside was completely warn out.

Bernard Lee DeLeo said...

Thanks for the update, Anon. I'm glad you were able to get it fixed.

Anonymous said...

Bernard,
I have an 05 Ford F-150, the engine was recently replaced by ford due to a cam phaser failure. It had this same issue before the engine went out. While driving on the highway if you let off the accelerator and coast then reapply the accelerator, if you apply to quickly it is like you have a dead spot for a second and it will backfire through the intake. Also if you are at a stop sign waiting to get into traffic and if you apply the accelerator to much to quick, same thing, backfire through the intake. It is also getting terrible gas mileage. When they replaced the engine they cleaned the fuel system/injectors and I replaced the TPS thinking it may be that. It wasn't. There are no codes or check engine light. Any ideas?

Bernard Lee DeLeo said...

Anon, I’ll assume you have a 5.4L engine. Without codes I can only guess at a couple of things you may not have checked. Most everything that causes a backfire through the intake will set a code or could be diagnosed with an in depth look at scanner Mode 6 data. Some items that can act up without always setting codes, but will affect gas mileage are: the mass air flow sensor, plugged up catalytic converters causing excessive backpressure, and there is a Fuel Pump Driver Module located above the left rear of the spare tire which can and does get corroded. Other than those, it would be a good idea to check all power and ground connections that may have been left loose after the engine change.

Mike said...

Hi Bernard - awesome blog. I have a 2006 Expo with a 5.4 and starting having the fail safe issue without logging any codes. After researching, including your blog, I replaced the TPS. Happened again and the last time actually logged a 2104 & 2112. I know the next step is replace the throttle body itself. My question is - I see Dorman makes a throttle body actuator (motor), part 911102. Since the throttle body isn't much more than the actuator and the TPS as far as electronics, what do you think about replacing just the actuator instead of the whole throttle body, so $60 instead of $300?

And either way - do you have to reflash after changing the throttle body/motor?

Thanks for sharing your expertise,
Mike

Bernard Lee DeLeo said...

I'm sorry, Mike, but I wouldn't do it. I replace the Ford Electronic Throttle Bodies with OEM parts. I can't advise you on aftermarket products. I can confirm what you've already heard, those multiple codes mean the ETB needs replaced.

Mike said...

Ok. Do you know if you have to reflash after swapping out the ETB?

Bernard Lee DeLeo said...

I have not had to reflash any yet, but whenever I disconnect the battery, I have my memory saver plugged into the OBDII socket. If the battery is disconnected, the computer goes to default settings. That will cause problems over a few days until the computer relearns the driving and idle parameters.

FRANK said...

I HAVE A QUESTION ON MY FORD EXPLORER I PUT NEW BRAKE PADS AND NOW WHEN DRIVING THE BRAKE ACTS FUNNY ,HIT PEDDLE IT FINE TILL CAR ALMOST STOPS THEN PEDDLE SINKS .HELP PLEASE. THANKS FRANK NYS

Bernard Lee DeLeo said...

If the fluid level is fine, Frank, and the pedal sinks to the floor at a stop, it means the master cylinder is bypassing internally, or something happened to one of the calipers during your brake pad replacement. Take it in to a shop for repairs.

Anonymous said...

I found your blog looking for an answer to issues with an 07 F350 with engine performance problems and codes P061B and P2106. The mechanic replaced the throttle body and throttle body sensor but the performance problem remained. After a few hours and all my uneducated suggestions I found on the internet, it turned out to be a wire from the throttle body sensor was rubbing and shorting out. Just thought I would throw in this solution in case it helps someone else.

Tom Woodworth said...

I have a 2004 ford f150 5.4L with 50,000 miles. My CEL came on 2 weeks ago and code P2106 showed up. I had ford replace the TPS. Ran fine for 2 weeks and now I have the same code showing up. Any suggestions?

Bernard Lee DeLeo said...

Tom, you didn't mention any symptoms you're experiencing, either before or after. If you're not experiencing any other symptoms, you may have to have Ford reflash the computer.

Tom Woodworth said...

Acceleration stops at about 2800 RPM. Kind of sputters and hesitates. Comes and goes though. Happened after 500 miles out of 1000 mile road trip. Now it seems to be fine as in no sputtering and has full acceleration but the code still remains.

Bernard Lee DeLeo said...

Since you are not experiencing any symptoms now, Tom, I would keep driving it for the next couple of weeks and monitor codes. It will be important to note if the computer turns the code off by itself. If it doesn't, and no other codes show up or symptoms, you will probably have to get the computer reflashed.

Tom Woodworth said...

Hooah thank you Bernard

wildlifeman said...

We filled up with gas & shortly after when slowing at stop it acted like it wanted to die ,little after check engine light came on it only acts like going to die at low rpmwhat do you think? Sorry its 05 Ford f150 parody 5.4

wildlifeman said...

I have 05 f150lariet we filled up with gas today shortly after it acted like it wanted to die when stopped thenlittle later check engine light came on it still acts like wants to die when idle

Bernard Lee DeLeo said...

I don't believe in coincidences, WLM. If you experienced this right after getting gas, you may have gotten a bad tank full. You can go and buy a couple bottles of Chevron Fuel Injection Cleaner and put it in the tank to try and get you through until the bad gas is gone. I can't tell you much more without knowing what codes set to make the check engine light come on.

frank nys said...

hey berni i have aproblem with abs light comes on then goes off could this be from a bad cv axle jointbrakes feel a little spongy, thank you frank

Bernard Lee DeLeo said...

'hey berni i have aproblem with abs light comes on then goes off could this be from a bad cv axle jointbrakes feel a little spongy, thank you frank '

I replied yesterday to this Frank, but your comment was in the spam folder - A bad joint would cause the problem if it somehow messes up the wheel speed sensor. I imagine you've checked the basics: fluid level, speed sensor connections and harnesses, brake lights (a bad brake light switch or a bad socket in the back can cause ABS lights). Without knowing what code or codes are being set, I can't tell you much more.


Bernard

FRANK said...

hey bernard thank you for answering my question on abs lights the problem is it doesnt show a code,dont know what to do now thanks again for your help in the past as well thank you frank

Don AB.CA said...


Don AB.CA
Hi Bernard, Don here have 06 Nav 200000k Had vehicle warming up hop in notice engine light on Fail safe mode on. at first back up slugish pull forward rev motor a bit and it sputter, Turned off waited abit restarted it still sputtered. Try to reset failure mode with dash buttons nothing happen would not even allow me to go through The sequence which checks all the diagnostics. Fail safe mode stays on solid. Decided to shut down disconnect battery ground cable wait 20-30 mins reinstalled cable. Restart seemed fine for abit but motor got worse would let me back up or go forward, Turnoff ignition limbed into the garage, No coolant loss levels good, oil good.There has never been any issue or signs ever. I have mainly off 89 octane. do use premium on occassion pending gas prices,I filled up with 89 octane with about 2 hours driving prior. Havent pulled codes, will tonight also have picked up TpS sensor OEM. This goofy cowling on the lincoln is a pain the flexable cowling rear attaches how? I can't see that far back to the rear of the fire wall also once I get that off then the TPS sensor is accessable My Question is to line the tang up for the TPS do you have to remove the hard plastic air intake or if you note the position to install in the same as it comes off?? or can rotate the inside of the sensor to line up, hope this might make sense. Also upon completion I was told by Mechanic there are some certains steps to follow to reset to fuel mixture by running the vehicle for short while 10mins turn it off disconnect ground for 1/2hour to reset clear computer codes reconnect drive 40 mph remove foot from gas allow to slow down speed up. Do this acouple times and resets air/fuel mixture through computer. I'M changing the sensor on a hunch from my old reliable 01 Expediton, which had similar issue. The codes will tell the story, hope its not the the Throttle body assembly. Was told it is probably would be the Mass airflo sensor. What kind of tool is issued to disconnect the TPS sensor I cant see any clips on it also the hose right beside it cant see clips on it as well,because of that flexible cover you think ford engineers should try holding some wrenches one day out in the field. Your thoughts and opinions would appreciated for this repair. thanks /later.

Bernard Lee DeLeo said...

Don, I'll be glad to give you some ideas once you have diagnostic data, but from the tone of your post, I think you should take it in to a professional. Whenever someone works on a high tech vehicle like yours, the proper tools, and an OEM shop manual or dvd disc is a must. A code reader may not be enough to diagnose the vehicle either. Another thing to consider is maintenance history. What have you done in 200,000 miles?

Josh Folk said...

I have a 99 ford expedition with a 4.6 triton it takes five minutes of cranking before it will start if it starts at all when it warms up it runs great i have changed the fuel pump plugs wires oxygen sensors crank sensor idle air control valve and tps any ideas

Josh Folk said...

Have a 99 expedition with a 4.6 triton cranks forever before it starts if it starts at all when it does start and warms up it runs great but in cold weather it will rarely start have changed oxygen sensors plugs wires fuel pump crank sensor tps iatv even got a different ecm/pcm and took it to ford dealer to have it programmed and updated any idea whats wrong with it

Josh Folk said...

I have a 99 ford expedition with a 4.6 triton it takes five minutes of cranking before it will start if it starts at all when it warms up it runs great i have changed the fuel pump plugs wires oxygen sensors crank sensor idle air control valve and tps any ideas

Bernard Lee DeLeo said...

Without computer scan data, I can't help you, Josh. Have you had your vehicle checked for codes? Do you know whether it has good compression? Does it run smoothly after warm-up? Have you had the electronic throttle control changed?

Bernard Lee DeLeo said...

It may be as simple as you using cheap fuel, Josh, or as major as the fuel injectors being partially plugged. As I stated I can't help you without scan data. If you left it with a professional overnight, I have a hard time believing they couldn't find out what's wrong with it cold.

Tammy Williams said...

I have an '07 Exped EL with 95,000 miles. Mostly on hills, it feels like it is missing or misfiring? I leave off the gas and put on gas again and it will be fine. it doesn't do it all the time but at least once a day and some days even on flat surface. I took it to ford and they got codes p0600 and p2105. they reset and not codes came back. worked fine for one day and started doing same thing again. they said if it came back that I needed pcm replacement with an estimate of $1000.00. Does this sound like a correct diagnosis or should I try something else?

Bernard Lee DeLeo said...

Tammy, I can't tell you much with that limited information. An ignition misfire can cause the same codes because a misfiring coil on plug assembly misfiring can feedback through the harness and cause a computer glitch.

1. Have you ever had the spark plugs and coil on plug (COP) assemblies replaced?

That particular tuneup is in excess of a thousand dollars, but you are at the right mileage for those COP's to start acting up. There is one on each spark plug and they are expensive.

When I get one in like yours, I first do a computer check, and use the Scanner Mode 6 data to tell me if there are any misfires, because many times the simple code check won't reveal the misfire. If it is misfiring on the Mode 6 data, I would sell a package deal with plugs and COP assemblies. Ask the dealer if they checked the Mode 6 data for misfires. If they didn't, they need to before condemning the computer.

There are a couple places where the harness rubs through on those. One is behind the oil dipstick tube, and the other is routed around the EGR tube.

Tammy Williams said...

when I took it to the ford garage that was my guess, to replace the plugs and coils. I don't want to replace the PCM and still have the problem. thanks

Bernard Lee DeLeo said...

Tammy, if you can't get the dealer to do a scanner Mode 6 test for misfire, find an independent who has the expertise. You'll have a much better idea you're on the right track if the Mode 6 scanner data indicates misfires. You've probably already paid the dealer for the computer check though. If they didn't do the Mode 6 test, then they owe you.

Tammy Williams said...

Thanks Bernard. I will do that. I hate taking it there and they start repairing things that don't need repaired and then I pay double or more and many trips back until they get it right.

The last three times I have had it to the local ford garage, my tire tread has been measured different each time, the first time they needed replaced soon and this last time (4 months later) they were in excellent condition. I wonder if they even look at them.

Sheryl Williams said...

I have a 99 ford expedition 5.4 Triton V8 4x4. The problem first started when I lost reverse, had the transmission rebuilt and once again had the same issue. Had the transmission rebuilt a second time still has some shifting issues. Replaced the TPS, the range sensor along with the starter ground being reconnected. Now no matter what the transmission shifts hard into every gear. At 70 mph its at 3500rpm's I don't think that is acceptable. I have been told to do a reflash however that is expensive and I don't want to waste money. I could use some advise?

Bernard Lee DeLeo said...

Sheryl, I can't help you without scanner diagnostic information, including Mode 6 comprehensive readings that can detect misfires. Also, you didn't mention who rebuilt your transmission. Was it Backyard Bob's tranny specialists, a dealer, or a good independent shop - and why didn't you pursue the problem further with them? Here is a tech service bulletin for a cracked ball inside the tranny valve body that may have been overlooked - http://ww2.justanswer.com/uploads/bobover/2010-01-23_231853_percievedlackofpower1-2f150.pdf

I'm sorry, but I'm not a magician. Without data I can't make even a guess as to what's wrong. It seems to have started with your tranny rebuild. Until you get that right, throwing parts at it without a diagnostic basis will be a heck of a lot more expensive and will solve nothing.

dremund glenn said...

99 navigator i put a tps on and still doing same thing

Bernard Lee DeLeo said...

Dremund. No info, no scan data, no code info, no problem description, no indication whether you bought aftermarket or OEM parts, so sorry... no comment.

wanda titus said...

I am trying to repair 07 F150 , tossing out multiple throttle codes, all systems seem to check out. FTMD , pump, throttle body, tps, question is, should the cruise control switch remain on when you shut it off, and can cruise control disable the throttle pedal?

Bernard Lee DeLeo said...

Impossible for me to say without scanner data, Wanda. When you get multiple throttle codes, it usually means the electronic throttle body needs replaced. You didn't mention what codes were showing up.

wanda titus said...

This is an older post , hope fully you still have answers :D . Should the cruise control switch say off and remain off on my scanner when you shut it off?

And ,, will a continuously on * cruise control stop the fuel system from working . mostly throttle pedal? The throttle body works , there is fuel pressure, sometimes the pedal works, and even when it doesn't the voltage and position do show in the scanner. The FPMD was badly corroded and has been changed. We are in proccess of changing fuse panel because there is water in taht right side panel?

Teresa Brewer said...

Ok 2001 ford f150 with 220,000 plus miles, 5.4 engine 2 wheel drive, throttle seems to be hanging in closed position, tapping on tps will allow engine to crank. Sometimes engine turns over but no crank. Changed tps sensor 3 times from 3 different dealers still have problem. Usually after sitting for a while and engine cools off am wondering if sensor is getting stuck or if throttle body could have enough wear to cause the tps to stick closed. No codes. Ideas? Thanks Teresa

Bernard Lee DeLeo said...

Sorry I didn't see your post earlier, Wanda. I'm sure that wet fuse panel was your problem.

Teresa, I can only guess here, but it may be your on board computer is at fault.

Anthony Millington said...

hey having a problem with a 2000 expedition with the 4.6. transmission shifts fine did a full tune up and chancged the mass air flo sensor and fuel pump and fuel filter so far. when your driving it will drive fine as long as you keep your foot between quarter and sometimes half throttle. but if you go over half or try to "gun it" she doesnt go anywhere and in some cases acts like she is even slowing down. but the rpms go up.

drankinatty said...

Bernard - great article, keep up the assault. You should make a few additions concerning the plug breakage issue. Specifically follow the Ford Technical Service Bulletin (TSB) 08-7-6 and do NOT use WD-40. Instead, use Sea Foam Deep Creep which is far superior in freeing the plugs. Follow the TSB carefully. When it gives the torque and time limitation, follow them. I extracted all 8 plugs from a 2005 5.4 expedition and 104,000 miles without any issue. What a relief. Keep pup the good work.

Bernard Lee DeLeo said...

Sorry to not have seen your post Anthony. If you have TPS codes with that problem, you very likely have electronic throttle body problems.

Use any method you're comfortable with, Drank.

Anthony Smith said...

Any way to recalibrate the tps? Mine shows 17% at no pedal and 87% at full pedal per my scan tool.

Bernard Lee DeLeo said...

Anthony. No, there isn't except on the old ones you could loosen and adjust. It's possible your throttle body may be gummed up enough to cause those readings, depending on what vehicle you're writing about.

John Mike McCall said...

I have an 05 expedition and the transmission is slipping when going into overdrive. I can turn over dive off and it runs ok. Does this sound like maybe a TPS or a solenoid ? Hope it isn't something really bad.

Bernard Lee DeLeo said...

No, it doesn't, John. Without scanner information and codes, I can't venture a guess. You should take it in to a reputable shop and have it checked. One thing to consider is mileage and if you've ever had the transmission serviced properly. If there's high mileage, and no servicing, you are probably in for trouble.

joshua lopez said...

I have a 2007 ford f150 5.4. I've changed the cam sensor and tps. It immediately goes into limp mode. I've cleaned the throttle body as well. Multiple codes show up now after I changed the tps. What do I do now?

Bernard Lee DeLeo said...

I don't know, Josua. You didn't list any of the codes either before or after the TPS. If you're still getting Throttle codes, the electronic throttle body may be the culprit, but as I said, you didn't list any of the codes.

Marc Seguin said...

I have a f150 2008 5.4 3 valve triton the codes p2101,p2104,p2110 & p2135 the truck idels rough and the gas pedal no response i have changed the throtol body for a used one still nothing could it b that it was defecteve to or .... I have changed the hole gas peddal asbley and still nothing HElP pleas
Marc.siderman.seguin@gmail.com

Bernard Lee DeLeo said...

Marc, the reason so many of these throttle bodies get replaced is because they don't last, so putting on a used one was not a good idea. I'm afraid your only option right now is to replace the throttle body with an OEM NEW one, erase the codes, and see what new ones if any show up.

Unknown said...

I have a 1998 ford expedition xlt 4x4 it has the 5.4 and to get it to go into drive I have to get the rpms to about 2500 and then it goes after that it shifts fine no problems what could this be

Bernard Lee DeLeo said...

As has been stated numerous times in the post comments I can't tell you anything without scanner data and codes, Unknown.

Katrina Mcvaugh said...

I have a 1998 Ford exposition 5.4l v8 when I start it it sounds like the gas is to the floor and if I put it in a gear it takes off and it's hard to get the brake down to stop. Everyone says the throttle cable needs to be replaced others say the tps sensor not sure what to do had autozone do test only things that come up are o2 sensor and 8th cylinder misfire. Can you help me out.

Garrett Britton said...

i have a 2006 f250 5.4. when driving it down the highway in overdrive and you mash the throttle it will die, wrench light comes on along with overdrive light flashing. i have had the throttle body replaced, mass air flow sensor, computer , even put a new transmission in it. it is still having the same problems . Any ideas?

Bernard Lee DeLeo said...

Katrina, The electronic throttle body can cause that problem, but it usually sets throttle codes. I recommend you get it checked at a dealer or reputable independent. That misfire will have to be addressed too. If you ruin the catalytic converters with misfires you will be in for a huge expense.

Garrett, Unfortunately, I'm not a magician. The only way to pursue a problem is to keep finding out what codes are reappearing along with Mode 6 diagnostic information. Yours is as with Katrina's a problem that must be checked physically at a dealer or reputable shop which guarantees their work. I have no idea what maintenance work you've done, but here's a repeat of the extra stuff I've found from the original post. Also, if you replaced the electronic throttle body with an other than OEM part and did not get it reflashed even if it is an OEM, then depending on the codes being set now, it may still be the problem.

1.If you have multiple throttle codes, it will almost always mean an electronic throttle body replacement along with the throttle position sensor.

2.The wiring harness running behind the Exhaust Gas Recirculation tube chaffs through the harness wiring and causes a multitude of goofy sensor and code problems.

3.They have updated spark plugs for these. In a related note, misfiring coils and spark plugs also cause an array of unrelated codes. My advice is change both the spark plugs and individual coil on plug assemblies every 60,000 miles.

4.The alternator going out on the Expeditions can and does cause electronic interference, disrupting engine and transmission operation.

5.A link to the Technical Service Bulletin for Transmission and Drivability problems related to a check ball breaking inside the transmission valve body.

6.I came across myriad problems in the East and Midwest after much research where a leaking windshield leaks water into the fuse box. The fuel pump relay is built into it so the fuse box has to be replaced when leakage is found. If the C270 dark green wire at the fuse box has no power it would point to corrosion in the fuse box. That could also cause myriad weird other electrical problems.

kim moore said...

Hi Bernard,

I ran across your blog, and I hope you are still reading and responding to these issues. I have a 2006 Ford Explorer. I had the whole Throttle Body replaced on Saturday and my car seems to driving worse than ever. I replaced the TB because while driving, and pressing the accelerator my car wouldn't go any faster and RPM's would go up very high. The wrench light came on, but went off after I turned the car off. It never came back on, but my mechanic suggested changing the TB. My car would only do the weird RPM/Accelerating thing infrequently, but since my mechanic changed it, it has been happening on every driving trip. Never got any codes. Any suggestions???

Bernard Lee DeLeo said...

Kim, I'm sorry I didn't see your post earlier. I wish I could help other than advise you to seek out a competent diagnostic technician, but without codes or data, I can't make an intelligent guess. There could be any number of basic troubleshooting steps being overlooked. It may even be the vehicle's computer would need reflashed after the electronic throttle replacement. Guessing and throwing parts at it can be expensive and frustrating.

Lori Bernstein said...

Hello Bernard. I have a 98 Expedition having problems with I believe the fuel system I have replaced spark plugs and at times it seems to idle fine took it out for a road test and the gas pedal seemed to delayed response even flooring it then would rev to 3000+ rpms seemingly in neutral then tranny would respond but lurch. I have replaced the fuel filter intended on testing fuel pump pressure but test kit did not include an adapter for the schrader valve. Tried unplugging both TPS and DPFE sensors with same result. Rough idling, rpm bouncing between high 1200 to almost stalling then recovering only to repeat the process. from start revs high then smoothly momentarily then back to bouncing rpms. I have connected a scanner and the codes came up for exactly the two items I unplugged, after clearing the codes by power interrupt, no codes found from your blog I suspect the TPS. I guess my question is >>> by unplugging the sensors I created the prob the errors, but the ce light came on while test driving before i unplugged them. I was just trying to see if either of those would worsen the condition. Anyway after clearing the codes the cE light did not come back on but the problem did not go away. Also I cleaned the gum from the large butterfly on the throttle body but did not remove or clean entire throttle body. Should I just replace tPS to begin or remove and clean entire throttle body first?

Bernard Lee DeLeo said...

Disconnecting sensors to troubleshoot is a bad idea, Lori. No, I don't recommend doing anything else other than returning to basics: fuel pressure, ignition misses due to misfiring COP's (coil over plug assemblies which should have been replaced as a set when you did the spark plugs) and in a 1998 vehicle exhaust back pressure should be checked. Plugged catalytic converter assembly or misfiring COP's would be my guess if no codes reset and fuel pressure checks out. The Expedition in my post was a 2005. They are not the same as a 1998.

Lori Bernstein said...

Thank you Bernard, your comments are much appreciated if I ever get this thing back on the road I'll have to read one of your books I've not read any yet, recommend a starting point?

Bernard Lee DeLeo said...

I hope you can get it back on the road easily, Lori. Yeah... if you read and like Peace, you would like anything and everything I write. Because of its length, Amazon gives you over six full chapters free in the 'Look Inside' preview. Sample the freebie, Lori. If you like it, you'll like the way I write. Here's the copy and paste link: http://www.amazon.com/gp/product/B00KSPCD34?ie=UTF8&at=aw-iphone-pc-us-20&force-full-site=1&ref_=aw_bottom_links

tree frog said...

I have a 98 Lincoln town car 4.6 runs great in park I can hold the gas halfway open all day but when I put it in gear an go it will run up to 30 or 35 mph then acts like it's running out of gas or bogs down for bout 10 seconds then picks up an Go till it hits 30 or 35 again then does the same thing again. I checked fuel pressure on the rail it's good fire is good to I put a new mass air flow sensor on no change I'm thinking it's a relay or sensor can you help please it's driving me up a wall trying to figure it out. Thank you in advance

Bernard Lee DeLeo said...

Without diagnostic info I can't even make an intelligent guess, tree frog. You have to have it scanned for codes and data. Otherwise you'll be guessing and throwing parts at it.

Looneytic33 said...

Bernard, I have a 2003 Ford expedition Eddie Bauer. It runs fine while driving and idling when I'm at a stop light, but when I put it in park it starts idling between 1200 and 400 rpm. I've replaced the IAC,the EGR valve. I've fixed all vacuum leaks, could it be the TPS?

Bernard Lee DeLeo said...

Looney - You didn't include codes, or any computer diagnostics. If you have multiple TPS or Electronic Throttle Body codes, then you probably have a faulty Electronic Throttle Body, but you need to have it scanned and professionally diagnosed. Otherwise you will continue to throw parts at it, and not repair the problem. You probably missed this section in the blog too:

01/12/12 - With so many comments on this post, I decided to add an addendum to it covering some of the further items afflicting the Expedition. Here’s a list of some things I’ve experienced with these.
1. If you have multiple throttle codes, it will almost always mean an electronic throttle body replacement along with the throttle position sensor.
2. The wiring harness running behind the Exhaust Gas Recirculation tube chaffs through the harness wiring and causes a multitude of goofy sensor and code problems.
3. They have updated spark plugs for these. In a related note, misfiring coils and spark plugs also cause an array of unrelated codes. My advice is change both the spark plugs and individual coil on plug assemblies every 60,000 miles.
4. The alternator going out on the Expeditions can and does cause electronic interference, disrupting engine and transmission operation.
5. A link to the Technical Service Bulletin for Transmission and Drivability problems related to a check ball breaking inside the transmission valve body.
6. I came across myriad problems in the East and Midwest after much research where a leaking windshield leaks water into the fuse box. The fuel pump relay is built into it so the fuse box has to be replaced when leakage is found. If the C270 dark green wire at the fuse box has no power it would point to corrosion in the fuse box. That could also cause myriad weird other electrical problems.

Unknown said...

hey bernard got a good one for you 04 f150 5.4 3v misfires under light load but only when you go to pass or are towing at wot usually as truck reaches around 4000 rpm , p0308 all the time p0358 1 time, not always miss at wot only under slight load condition, i have replaced all cop, all plugs #8 2 times. for p0358 replaced pcm rewired primary circuit bypassed secondary circuit, replace injector, cop connector and fuel pump and filter just because, runs perfect or all other conditions the symptoms have not changed any, trck has 375000 miles but in excelent shape,makes it hard to pull a camper up hills like this, when I induce it will miss until I release throttle and after 15 seconds +- miss stops like a switch fliped, also cats removed until thhis is resolved thanks in advance,

Bernard Lee DeLeo said...

Unknown, if compression is normal in that cylinder, I would suspect a slight vacuum leak over the number eight cylinder which only affects the vehicle under heavy load by leaning out mixture to the point the computer and fuel injector can't compensate. If at idle speed the RPM's seem even a bit higher than normal, that would be my guess, especially if it also sets an oxygen sensor code for that bank occasionally. You may need to take it to a shop with a 'Smoke Machine' to find the vacuum leak. Check any vacuum hoses mounted near it on the manifold.

Shannon Seymour said...

Bernard - my '06 Accord has been jerking and hesitating for over a year now. I have taken it into 3 separate shops, explaining the problem and suggesting perhaps the fuel filter (located inside the fuel pump) needs to be replaced. Not a single shop found anything wrong, and no repairs have been made. Last week the check engine light came on and the code was for the throttle position sensor. I took it back to the shop, but since the engine light went off, he made no repairs. Ughh. I want to address the root of the problem: is it possible the fuel filter or pump could affect the throttle position sensor? Or do I just need to beg to have the sensor replaced? Many thanks!

Bernard Lee DeLeo said...

Shannon, it's possible for a fuel problem to cause a few different types of codes, such as lean oxygen sensors, or even cylinder misfire codes. Have you tried letting the tank run down to an eighth of a tank and filled it with premium name brand fuel such as Chevron or Union 76? I would try that first. Other possible causes for the hesitation are torque converter and plugged EGR ports in the intake manifold. I'm sorry, but you'll have to find a shop more interested in doing the basic checks like fuel pressure and possibly clearing the codes to see if any reset after marking them down. If you've been using cheap fuel, try the premium if the check engine light is out and see if it helps.

Shannon Seymour said...

Thank you, Bernard. I have been running premium fuel since the problem started and used Seafoam additive twice over the past year. The premium fuel seemed to lessen the occurrance and degree of hesitation until recently. Sadly, there are no other shops in the area.

Kelly Gatts said...

Bernard,
I have a 1997 Ford f150 4.2L 4wd lovingly (or not) dubbed the truck from H___. From the day I inherited it it has been one problem after another. My current situation is: while driving down the street at about 29mph the gas pedal would rev but quit delivering power to the drivetrain. Their were no prior indicators of anything wrong with transmission. shifted fine right from start up. It has now sat for several months. I put some seafoam and 5 gals of fresh gas and it starts and runs fine. I've only ran it for about 5 minutes. put a code reader on it and codes p1537 & 1538 come up, intake manifold runner control banks 1&2 stuck open. Called around and noone has heard of such a thing. Any ideas? thanks Kelly

Bernard Lee DeLeo said...

 I can only guess, Kelly, but usually when both those codes show, the problem is the IRMC at the back of the block. The upper intake has to be removed to reach it, and like I said, it's a guess. Here's the definition:

An intake manifold runner control is an electronic system that gives data regarding linkage and plate position to the powertrain control module. The IMRC is housed inside an aluminum casting that stores a motorized actuator with air passages for each cylinder.

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