'88 weird idle problem

I just picked up an '88 4.0/AW4/231 about a month ago, it just sat in my garage until the fuel pump on my truck went out saturday....I drove it home fine, then it was starting fine, but not idling at all, after a few cuss words and my mechanic friend, we found out it was the IAC, took it off, cleaned it and now it starts, idles and runs just fine. The problem is that when i'm driving it and let off the throttle to come to a stop, it idles pretty high, i'm guessing in the ~1500rpm area. If i blip the throttle a bit, it will come right back down to normal. What could be the culprit?


Sometheing sensor/electrical related?

It does have a problem with the throttle sticking a bit...that might be it? It seems to be binding up where the throttle bracket bolts to the engine, the spinning lever thing that has the cable on the one side and the little arm thing on the other.....i took it out and found it will stick when i fully open or close it....seems to me it shouldnt do that


Sorry for the long post, i tried searching but with no luck

Thanks, Dan

I would clean and oil the IAC again, and pull and clean the throttle body. The EGR on that year builds up carbon deposts in the throttle body and IAC areas that makes the idle stick at times.

Also use the advanced search tool to search for a thread title of "RenX Files" for a long painful run down on idle and ground and TPS issues, etc. on your jeep, that you will want to bookmark.

Right now it sounds like it just a needs another cleaning (the IAC) but this time clean the throttle body port too, that the IAC seats into where oily carbon trashy deposits can get hung up. Spray cans of Carburator cleaner work great on those two parts.

Yeah I cleaned the IAC port and throttlew body really good when I did the IAC

I guess i'll keep reading


Thanks, Dan

One of my sources of a random high idle problem was a loose floor mat that would work its way up against the throttle cable under the gas peddle. :shiver:

:banghead::banghead::banghead: