1990 Jeep Wrangler Engine Trembles

  • 4 CYL
  • 4WD
  • 139,000 MILES
We just bought this about 2 weeks ago. The engine was working great. Now, for some reason the engine has begun to tremble in idle. We have checked the cylinder compression, they are all at 105. Has new spark plugs, cables, distributor cap, and rotor. We can not figure out why the engine is trembling or shaking. Have gone thru everything and do not know what else to check. Help!
Do you
have the same problem?
Thursday, April 8th, 2010 AT 7:32 PM

1 Reply

This may help. OR NOT. Just a member here like you. Unpaid, Hobby right now, Injured at work 15 months ago, recovering now, ready to go back soon. Please See my profile. I answer what I am familiar with.

Written/experienced by me and sent to several other people w/ similar situations at this site. Pasting.

Our Escape would idle low, then it got to point it would die when you stopped. Reving + holding brake was only way to keep it running.

Took it to fellow R/C airplane pilot, he doubles as a S.C. State HWY DEPT mechanic.

When I got to his house, he was repairing a tractor. Told him my sob story. Escape was still barely running, I raised the hood.

He said, (and I quote)."It could be the IDLE AIR CONTROL (IAC)", as he pointed to it, and emphasied it with a sharp rap using the wrench in his hand.

It straightened right up, and ran damn good!

That was a 15/16 Craftsman wrench, box end, kinda a medium rap.

YES, I visited parts store and replaced it.

Hope this helps

. Unpasting.

This, IAC, is sorta a bypass for air to get into your engine, when the "main butterfly" (throttle plate) is closed.

It is strictly opened in certain, fluctuating amounts, by the COMPUTER, to allow air in, for precision IDLING

Buddy also said I could clean it.

Took no chances, its WIFEs rig.I did replace it.


SIMPLE INSIDE. He said clean moving parts leave motor alone might pay to clean it and try it, if for no other reasonto VERIFY IAC is problem.

Clean/Replace it, if you are now certain this is your evil part. Up to you.

This may not be your problem, it was for our Ford Escape. Your rig is using same technology.

Saw you had no replies yet, I know the "Deal" when your Jeep is off-line, for any period of time. (Lots of crying)

A manual will aid you alot, now and later, about $30 at major auto parts store. ---Really--- read thru it, even if you have no repair to make. Lots of eye-opening stuff in there!

I answered you here, to at least give you something to go on, maybe EZ fix for you!

Hope I helped, send back results.

Love, Turddog
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Friday, April 9th, 2010 AT 10:23 AM

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