Engine hesitates with accelerator push...

[Jake's Dad]

V8-X:

I know you have replaced many parts recently - but have you replaced the PVC valve??

JD

 

[V8-X]

PCV was actually changed with the fuel filter, about a week after the plugs & wires were changed.

 

[ChuckyD]

I had a very similar problem to what u are describing, and when I changed my TPS it stopped.

I could never duplicate the problem when i wanted to, it would just happed at any speed except WOT.

 

[Jake's Dad]

Chucky D:

Did the TPS trigger the check engine light?? My CEL is not on currently.

V8-X:

That figures. I was hoping that the probelm was the PCV valve.


This has to be something simple here - but what I dont know.

ARRRRGH!!!!

Jake's Dad

 

[V8-X]

My problem wasn't corrected with a new TPS unfortunetly. I am unable to duplicate the problem when I want. It has a mind of it's own. I can tell even when it's not acting at it's worse, that it doesn't have the power that it once did. Even at WOT I have problems sometimes picking up speed.

The TPS did not trip the CEL. The only time the CEL has been tripped was when the #4 plug went out. Since the plugs & wires were changed, the CEL has not come on again. I just have a overall lack of power, that is worse at times.

 

[ChuckyD]

Originally posted by Jake's Dad
Chucky D:

Did the TPS trigger the check engine light?? My CEL is not on currently.


Jake's Dad

Nope

 

[Jake's Dad]

I would go ahead and replace the TPS, but V8-X has the same problem I do and he replaced his with no improvement.

Man this really stinks!

JD

 

[Alec]

The TPS isn't that expensive and you could either return it if it doesn't help or keep it as a spare. Autozone will take it back if it looks clean.

 

[V8-X]

I'm not saying we have the exact same problem, but it does sound like we are having the same problem. A bad TPS may give the symptoms that we are experiencing, but I have ruled the TPS out since it did not correct the problem. Maybe you want to remove the TPS and check the voltage to insure this isn't your problem. You never know. Like Alec stated, they're not that expensive to replace. I paid something like $30-$40 for mine straight from the dealer.

 

[Jake's Dad]

Well I guess Ill try the TPS. I think Auto Zone wanted like $32. At least I'll cancel that out and see what's up.

JD

 

[V8-X]

It's a start, and if not the problem you can always return it. I would just keep it for the future, just in case. But that's me. Hopefully this is your fix, good luck!

 

[Jake's Dad]

Autozone will sell me one for $31.99, cheaper than anyone else I have found.

I wonder what that noise is behind the engine though. It only happens when the engine is stressed from acceleration.....or if you really push it.

Strange.

JD

 

[wmak8]

I am having the same problem that Jake's Dad is having. I have noticed a drop in performance for the last 6 months. The check engine light pops on and goes off in a couple of days. The worst of it came yesterday when I started it in the morning. The CEL was already on. The engine ran rough at idle. When I got on the freeway, acceleration was worse than before. The engine missed a few times as I was accelerating from a slight grade at 1500 rpm. Made a couple of popping noises from behind the engine or close to the catalytic converters. While all this was happening the CEL was blinking. Truck jerked a little and scared the hell out of me. I brought the truck to a local service station near my work and they checked the engine codes. Told me that one of the O2 sensors needed to be replaced. Did that and it is still the same. Now they think I need a tune-up. The truck has 76k miles and I think it needs it too. So we will see what happens later today. Does anyone think the Catalytic converter may be clogged? I remember something like this happening to a Camaro I had many years ago. Had the Cats replaced under warranty and everything was good. Oh by the way, the X hesitates from every stop now. Shakes a little before it starts to go. Arrrrrgh!!!

 

[ChuckyD]

You replaced 1 of the o2 sensors?

doesnt your X have 4?
Did you check the PCV valve? Have you dont anything mentioned in this thread?

I hope that tune up works out for you!

 

[wmak8]

Yeah, I replaced one only. He showed me all four but he told me only one of them was bad. Is there going to be a problem if I only replace on out of the four. They checked the engine codes after the replacement and there weren't any error codes. I hope that tune up works too. If it doesn't, I will have to try the things mentioned on this thread. Seems like a lot of stuff could be the problem. Oh well.

 

[Jake's Dad]

wmak8:

Sounds like we have the same problem, only my idle seems to be ok. The problem always occurs around 1500 -1800 rpm's for me, too.

This is frustrating. It's cold here in Michigan - last thing I need is to be stranded somewhere in a snow storm!

JD

Ps. Let us know your verdict!! Good luck.

 

[wmak8]

Problem fixed!!!

Originally posted by Jake's Dad
wmak8:

Sounds like we have the same problem, only my idle seems to be ok. The problem always occurs around 1500 -1800 rpm's for me, too.

This is frustrating. It's cold here in Michigan - last thing I need is to be stranded somewhere in a snow storm!

JD

Ps. Let us know your verdict!! Good luck.

Hey Jake's Dad-

Have you done a tune-up yet? The tune-up fixed my problem. The culprit was plug wire #4. Apparently, there was some slack because the wire was quite long. Some of it was looped around and part of the wire was resting on the valve cover. Somehow, the wire was frayed and was grounding against the engine block. The mechanic showed me the wire and it looked like something sharp was rubbing against it. There was about 1 inch of the insulation that was frayed. The grounding probably caused the CEL to blink when I was accelerating from the small hill at 1500 rpm. When you get a tune-up, ask them what kind of plugs the X uses. I was charged $80 for the factory Motorcraft plugs. The wires were $118.00 and the fuel filter was $20.00. The total for the tune-up with labor was $398.00. I think a tune-up isn't due until 100k, so check your plug wires first. But if you are going to change those, you might as well do the whole thing. It sure is nice to have the power back. Good luck!

 

[Strike12]

I have many years experience working on all types of vehicles and couldnt help but notice your paticular problem . I had a ford 302 fi that gave me the challenge from hell . It had the same symtoms , starts and idles good , hot or cold , but stumbles , hot or cold , around 1500 - 1900 rpms . I replaced everything , short of any actual mechanical part . Well it was better after replacing the coil pack , but still stumbled . I took the vehicle to a buddy of mine to see if he could diagnos the problem . It turns out it was a bad coil pack , even though it was brand new , it still wasnt putting out enough secondary voltage . I put a differrent brand coil pack in and bingo the 3 month old nagging problem was fixed . I too had no codes stored . Hope this might help.

 

[Jake's Dad]

Wmak8:

Yes, I had a full tune up with Bosch plugs and new wires at 70k miles. I also replaced the fuel filter, and the IAC valve.

My friend Mike added these comments (he knows way more about this stuff than I).....

STRIKE12:

"I'm Jakes Dad's friend from work... just took a drive in the truck. It seems that the "amount" of hesitation is dependant on the amount of "load" that the engine is under. It seems that we feel the hesitation a bit more around 1500 - 1900RPMs because that's what the RPMs drop to when the torque converter engages in 4th gear. There's a bit more load on the engine when the converter engages, and you will feel more engine vibration/hesitation when the converter is locked.

When I went out on the freeway and drove around, anything past ~2/3 throttle makes it hesitate badly. And if you floor it, it just hesitates worse. Put it down to half throttle or less though, and it smooths out. Again... it seems load dependent (as in the more load on the engine, the worse it runs). Now... when the engine is under more load, it needs more fuel. J.D. had the work done to the truck when he got it (to keep it in tip top shape of course). I'm wondering if the people replaced the fuel filter at all. Anybody think it's a lack of fuel???

The coilpack theory crossed my mind as well... but lack of fuel seems more likely to me. You can rev it as high as you want with no load applied (in neutral/park) and it runs fine. No missing or anything. If you FLOOR it to rev it quickly, it stutters a little... even in neutral. Any ideas? - Mike"

I'l keep you all posted when if I get the fix!!

-JD

 

[Alec]

I forget, have you done the fuel filter?