Rough idle, not ignition related

zero_chance · Aug 8, 2007

Just wondering if anyone has had any experience with a rough idle while in park or at a stop sign, etc. The idle doesnt hunt or anything, but the entire car will shake every couple seconds. Not a misfire or ignition related, thats already been ruled out. Hooked up NGS and ran power balance three times and each time it came back no problem, even with the tighter guidelines. Car runs fine and doesnt lack power but when its stopped it shakes noticeably every other second or so. Just hoping somone might have some ideas to chip in.

ryclef331 · Aug 9, 2007

I'd say it just sounds like a cylinder stumbling every once in awhile....could be a plug fouling. If it doesn't cut out, I wouldn't worry too much about it unless it gets progressively worse. Otherwise, trying throwing fresh plugs in it, gapped correctly. whats timing set at? what gas do you run?

95Grandtouring5.0 · Aug 10, 2007

Mine did the same thing, It was my coil, i replaced it and it stopped, then after a couple months it started again and is doing it now, i'm thinking its the plud wires.

zero_chance · Aug 18, 2007

Yeah the only thing left thats still stock are the TFI module and coil but they wont be much longer... Im hoping one of them gets rid of it. Its more of just a nuisance than a problem. Still would like to get rid of it though.

zero_chance · Aug 28, 2007

Turns out its the harmonic balancer. I had to replace one on a 4.0 Mountaineer Saturday and the symptoms were identical so I gave mine a look... tada. Then I search it on here and find out its a common problem with these cars. Guess I should have done more research... :

ryclef331 · Aug 28, 2007

zero_chance said:
Turns out its the harmonic balancer. I had to replace one on a 4.0 Mountaineer Saturday and the symptoms were identical so I gave mine a look... tada. Then I search it on here and find out its a common problem with these cars. Guess I should have done more research... :

Don't sweat it...its a VERY common misconception. I bought a 95 GT from a guy for 1,000 b/c he though the motor was blown....I knew it was balancer I just kept my mouth shut.... ;D

zero_chance · Aug 29, 2007

Must have been hard trying not to smirk as you signed the papers on that one.... O0

Dr Fildo · Jul 16, 2008

Hey Zero_Chance, I'm about to replace my harmonic balancer on my '95 GT. I think I've narrowed it down to that (with a lot of help from the forum, thank you!). Was it difficult?? I have never done one before, so if you have any tips, I would really appreciate it. I'm going with an OEM replacement from NAPA, and I plan to rent the puller tool from my local AutoZone. How long did it take you? Any special tricks you used to loosen the nut on the crank?

Any help would be GREATLY appreciated. Thanks.

ant0045 · Jul 16, 2008

im having the exact same problem with my car...im gunna put the harmonic balancer in this weekend. thats a good deal on a mustang...i got a better one though on a 1999 cherokee for $200(aand it was in good shape with new tires) pep boys told them it needed a headgasget because it was over heating, i looked at it and the water pump was leaking and there was no coolant in it, replaced the water pump and my gf has been driving it for a year now lol...hopefully the balancer solves the idleing problem.

Dr Fildo · Aug 2, 2008

Hey Zero_Chance. My problem sounded just like yours, and replacing the balancer did the trick. Runs Smmooothe!

AHayes88 · Aug 4, 2008

Dr Fildo said:
Hey Zero_Chance. My problem sounded just like yours, and replacing the balancer did the trick. Runs Smmooothe!

Good to hear that fixed it. Were you able to check to see if that damper had slipped out before you pulled it?

Dr Fildo · Aug 5, 2008

No, actually, it looked fine before I pulled it, so I was kinda goin' on faith. It seemed a little off, though. Like it was a little loose around the rubber seal when I yanked on it gently, but it looked ok otherwise.