4.0 high idle intermitten

dyer91

dyer91

Active Member
Joined
Sep 7, 2006
Location
Greensboro
ok this one is getting to me a little. 91 yj 4.0 auto trany, sometimes on initial start up it jumps to 2000rpms and after a few seconcds will settle down. then when shifting from reverse to nuetral it will raise to 2000 again and it will settle down. i go to drive and its fine. go back to nuetral and it will raise again. it has come down to throwing parts which i can not stand. it has a new map sensor, iac, tps, computer and the tune up is in good order. any help would be greatly appreciated!
 
high idle

I know that you said you have replaced the IAC......what type did you put back on it, and have you tried tapping on it to see if it will bring the idle back down?? Make sure that the pintle is not more than 1 inch extracted out of its bore. Check to make sure there isnt any residue in the throttle bore behind it as well. Have you tried disconnecting the battery to clear the memory? These computers really have some stupids charecteristics. As far as a vacumme leak....does it have a exhaust leak when cold?? If so...I would be looking at the intake/exhaust gasket....but it would have to be one hell of a leak. Hope this is of any help at all.
 
throttle cable seems ok, iac is from autozone(i know), vacuum lines good. i will check more after the holliday, i am on my way to knoxville to visit the outlaws.
 
Damn, outlaws! I have to go to Charlotte to see mine.:shaking:
 
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