96 zj rebuild problems

New here to RME4x4. hoping someone can give me a direction to go....

i recently rebuilt a 4.0 for my 96 zj after trial and error i got the thing started runs awesome smooth and quiet. did engine break in. Was having a hard time idling so i cleaned the IAC valve ran a little better but still wanted to stall when i shifted into drive or reverse. next i changed the TPS and thought it was fixed it was idling better and wasn't dying when shifting into gear.. until the other day i have got about 30 miles on it and it all of the sudden not wanting to idle at all. died about a mile from my house and had to get pulled home. couldn't get it to start again. if i floor the throttle and then feather the throttle it'll start but no idle what so ever. if i get the RPM down to 800 or so it'll just die. i can't figure out what is going on. checked fuel pressure its about 47-49 psi while running. no check engine light nothing saying there is a problem.

i'm about to throw my hands in the air and give up on it. any tips or advice would be greatly appreciated.


Long Jeep Fan
Holladay, Utah
Test the IAC to make sure it is actually moving. You can take it out of the throttle body plug it in to the harness, turn the ignition on and off and see if it moves. I should have several of these laying around if you want to try a swap.


Registered User
Premium Member
Arm Utah
I had an XJ I fought for a long time and replaced the CPS twice. I ended up having to hard wire it and that fixed the problem.