Hello all. Wondering if anyone on here can help me solve some issues I have been having with my '00 Cherokee Sport's (4.0L, Auto) idle.

Up until recently, everything on the Jeep had been running smooth as butter. However, lately the Jeep has been giving me some issues with idling and throttle response. The problems are not constant. Most of the time she starts up fine and runs at normal idle (about 750-800rpm.) Occasionally though, I start it up and I get a very low idle (probably around 400-500rpm) accompanied by a vibration. The idle is so low it almost feels like it's ready to just stall entirely.

When the idle is really low and the Jeep is rumbling around like this, the throttle response is very low. On a few occasions, it is simply very low, as if the Jeep is trying real hard to build up RPM's but is doing it about 1/10th as fast as it normally would. On other occasions, the engine revs up fine until it hits about 3000rpm, at which point it goes back down to 1000 or so, and back up, and repeats this cycle (almost as if I was revving the engine and letting off, revving again and letting off again, etc.) while the gas pedal is all the way down.

I have been doing some reading on the subject and I am seeing a lot of people having similar issues who cleaned their idle air control valve and/or replaced their throttle position sensor. I wanted to see if anyone had input on the subject before I start throwing money at it.

Hope this is sufficiently detailed...I am not a very tech savvy person.

THANKS!!!

 

Have it read for codes then go from there even if theres no check engine light on.

 

Either or both of the items you mentioned can cause the symptoms you described. You can clean the IACV yourself.