Hesitation/Miss at Idle and Under Acceleration

Trixie

Trixie

Moderator
Staff member
I've recently developed a slight intermitting miss at idle and some really weird surging/miss/hesitation at acceleration, most noticeably under light acceleration.

I thought it might be a bad tank of gas, but around here it's not common to get bad gas, and it was just filled again and the hesitation hasn't gone away.

Any ideas what to look for? I can't think of anything exceptional that happened lately to cause this.
 
RE: Hesitation/Miss at Idle and Under Acceleration

If it were just missing, i'd say it was a bad coil. But if it's doing other stuff too, it might be some kind of sensor or something. Are you getting a check engine light?
 
RE: Hesitation/Miss at Idle and Under Acceleration

You didn't by chance just wash your engine did you?

If so there will be water in the 1 and 8 holes. Pull the cover and coil packs and dry out with a hair dryer.

If you haven't washed the engine I would still start looking at boots and coils. If a boot is bad you will see a crack in it.
 
RE: Hesitation/Miss at Idle and Under Acceleration

No check engine light. We haven't washed the engine in a while, but there was a big storm last week.

Plugs were replaced I think about 2 months ago, and the boots were all replaced last year, and must have still looked good.

I'm at work right now so I can't check any of this out, but I appreciate the responses and will be checking those things out after work.
 
RE: Hesitation/Miss at Idle and Under Acceleration

Any ideas what to look for? I can't think of anything exceptional that happened lately to cause this.
Click to expand...

Has someone been thrashing your car around lately?;)
http://mark8.org/users/trixie/pic/twinkisssig.jpg

Most likely it is a combination of problems, one brought about by the other or at least one problem enhanced by the other. A bad coil, boot, or plug would explain part of it, along with maybe a dirty MAF or air leak(note a vacumn leak is the same as an air leak)?
 
RE: Hesitation/Miss at Idle and Under Acceleration

When did you last change your fuel filter? Moose had a hesitation prblem last year under acceleration and right turns, replaced the filter and it ran like a new car!
 
RE: Hesitation/Miss at Idle and Under Acceleration

man i hate this computer. I have to add another reply just to see the 5 or so that were entered since i replied. You may delete this post at will.
 
RE: Hesitation/Miss at Idle and Under Acceleration

Hee hee. Let's blame the kid.

Driller, like I said, nothing out of the ordinary. ;-)

Now, driving home it was a very intermittent problem. Would that rule out the coil pack?
 
RE: Hesitation/Miss at Idle and Under Acceleration

Well, we're working pretty slow around here -- doesn't help that Hubby's car is a POS so he sees nothing wrong with mine when he takes it for a drive.

They replaced the fuel filter for me today, and prior to that, the kid only noticed what he felt was a miss at medium acceleration at medium speeds. Idle seems better now, but did seem slightly off, but I didn't take it out for a drive.

I'll try to get them to move on to step 2 tomorrow (I guess that would be air leak and/or MAF), and maybe by Carlisle 2004 my car will run right. ;-)
 
RE: Hesitation/Miss at Idle and Under Acceleration

I drove the car to work this morning, and it's not running as bad as before, but there still is a bog/hesitation under acceleration.

So would this lead me to believe it was bad gas? And if it's bad gas, would that foul the plugs?

We'll still check on the other stuff, I'm just trying to narrow down what we need to look at since it's like pulling teeth to get anyone to help with the car on the weekdays...
 
RE: Hesitation/Miss at Idle and Under Acceleration

Trixie:
I used to have 5.0 Cougar that would exhibit the same problems you are describing. It would be a reoccuring problem every 12 -14 months. The solution? I would take it to my mechanic and he would clean the fuel injection system (in addition to changing the fuel filter). The mechanic-in-a-car fuel injector cleaners would not work (STP, Wynns and so on). But the industrial strength injection service would cure the problem.

If changing your fuel filter showed marginal improvements, then going down the fuel injector cleaning route is probably a good way to go. Fuel injector cleaning service shouldn't be too expensive either, (less than $75 bucks).
 
RE: Hesitation/Miss at Idle and Under Acceleration

Well, get this. When Hubby was checking the plugs, there was water in the back two plugs. He dried it out and she seems to be running good now.

I can't for the life of me figure out why, since the enginge hasn't been washed since before Carlisle in May, that the problem just started now....

But thank you all for your input, and if she continues to run crappy (and even if she doesn't) we still have a list of things to clean and check to make sure she's at 100%. :)
 
RE: Hesitation/Miss at Idle and Under Acceleration

I know a good mechanic in New Orleans that could be seduced into working on it for you. Hell.... I'll even check out the car too!

What's up Trix!!!! Tell John that you are on to him washing the engine. He just needs to remember: step 1 - wash engine step 2 - re-gap plugs.

Steven
 
RE: Hesitation/Miss at Idle and Under Acceleration

BOOOOOOOOOZZZZZZZZZEEEEERRRRRRR!!!!!!!

I've missed you! You were my first (regarding mods at least) ;-)

Pet anything special lately?

Ever since we visited you, John avoids playing with the plugs and boots as much as he can.

:*
 
RE: Hesitation/Miss at Idle and Under Acceleration

Dear Randy,
If you are still out there, thanks a million!!! I just washed my engine and it starting coughing and spitting like it had the flu! The CE light came on (first timefor anything other than a belt change) and gave misfiring code and intake manifold code. I had been going through old posts to see if anyone else had this problem and I found your post. I will be opening and drying the #8 tomorrow.!! Thanks again LOD!!!

Gratefully,
Mark G.:D
 
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