I've got a 92 cherokee limited 4.0 and it just recently started having issues idling after driving for a mile or so. I had the alternator checked, but it was just fine (but it idles fine everytime i start it-the issues come after driving it). I've changed the fuel filter and ran a fuel treatment through the tank, i've disconnected the battery/reconnected it, changed the air filter. It keeps having the same problem and drops down to like 200 rpm at idle and then the batter level drops down, headlights dim, etc. What else could i do to try and fix this?

 

Do you have your CEL on? It's tough to guess what it could be.

 

The idle sounds like theIAC or TPS. Iwould try th TPS 1st. Pull it out and turn the bullit looking thing a little and put it back in. See how it is now. If that made things worse then try turning the oter way. Try it again. Good luck.

 

92 TPS is not adjustable but it almost sounds like your MAP sensor has failed as it helps to adjust the IAC valve during idle