Well my jeep has 252k on it. It has recently started idling funny. I noticed a few days ago that right after I start it up sometimes it will fumble when you hit the throttle to take off then it will go and not have a problem the rest of the time driving. I also noticed today that after I drove it for about 30 minutes I pulled up in front of my house put it in park then it started to idle at 1500 when it usually idles around 700. It has had the ECM rebuilt, new IAC, and TPS, distributer, wires, and plugs replaced in the last few months. Any idea what it could be?

 

Didn't adjust the butterfly on the thorttle body did you or maybe break the gasket? Good brand TPS?

 

It was replaced by the previous owner a few months ago. He was a mercedes benz mechanic and was really meticulous with the jeep so I would imagine it is a decent TPS.

 

vac leak maybe. id consider putting it on a code reader (even w/o CEL being on) to see if anything has stored. maybe refresh battery terminals, wires, grounds, clean and dielectric grease all connections under hood. general tune up- plugs, wires, cap, rotor.