I have a 1989 Jeep Cherokee Laredo 4.0L and im having a problem in that when I turn my truck on At Times it revs up to about 2500 to 3000 rpms and stays there in park without my foot on the gas or I turn it on and its revs below 1000 rpms strugling to stay on. I checked the vacum hoses and they look ok at first when it started doin this two of the hoses were disconnected but I placed them back and it was alright for a while but it started again, now when the 2 hoses where disconnected it idled alright but when I connect them it starts to act up. What could be the problem I also cleaned the throttle body and idle air control valve with carb cleaner.

 

Have you checked your TPS?

 

No not yet

 

I have a 89 too and had same problem . Tracked it down to the tps. Changed it and she is doing just fine now

 

Im gonna give it a try see how it turns out