I got a 1990 2 Dr jeep Cherokee that to me runs fine. but it needs a fix. Here's the problem: starts fine runs good at around 600 rpm's until it warms up sometimes when i'm driving and stop at a light it idles to around 1500 rpm constantly if i shut it off and start it back up in like 5 minutes it idles fine again. Any idea what it is......

 

IAC sensor... maybe

 

Same thing happened to me! I replaced the IAC= Idle Control Sensor, and the TPS= Trottle Position Sensor. Good luck on your find. Let me know what you find.

 

do you think my vaccuum lines would have anything to do with it cause i just replaced the pvc valve and there doesn't seem to be any pressure coming out of it when i pull the hose off plus if i don't plug my oil dipstick it shoots oil out of it even with just the dipstick in it shoots it out usually i have to put a rag or something around it then force it on

 

Yea It very well could be vaccum lines. Any Codes Pop up ? If so pull the codes and find out whats causing it. I would start with vaccum hoses, or it also could be sensors causing it to run rough. My first thought was Sensors. My Grey 88 XJ did run worth beans but found out it was 2 sensors now it runs awsome. If you have a Jeep Repair Manual that will help with the issue as well. Keep me posted on this issue. GOOD LUCK !!