Originally Posted by RB89XJ

I am having the opposite issue in my jeep. I have an 89 4.0L. Mine is stalling out because the idle is too low i think. I had the IAC valve replaced not too long ago, and that fixed it for a while. Then the jeep quit out on me and it would crank and but not start. I had the throttle body cleaned, and a new crank sensor installed. It starts now, but is giving me the same stalling problem. I had all the vacuum lines checked and they are fine. My resting idle is about 500. I am wondering if the jeep is idling improperly, and that is causing it to stall out. Maybe i need to replace the IAC again? I also have an emissions mat light on, so i was also wondering if that may have something to do with the issue. Maybe O2 sensor, CAT Conv, or something else?? Any ideas????