Hey guys,

Ive got a 94 xj with the 4.0 and aw4. Just recently my jeep has developed a rough idle. When I start the jeep cold it idles fine. As soon as it reaches operating temp the idle gets rough. It's not the rythmic chug chug chug of a misfire, just rough. After its been at operating temp for 2-5 minutes the rough idle goes away..... What could be causing the rough idle to come and go at very specific times like that?

I have recently replace the exhaust manifold with and apn and used a new gasket from the dealer. Spark plugs, wire, dizzy cap, rotor all have less than 10,000 on them. Did the 703 injector swap about 5000 ago. New mopar 02 sensor abouth 500 miles ago as well...

Any thoughts or comments are greatly appreciated. Thanks in advance!

 

When was the last time you gave the throttle body a good cleaning, including the IAC? Might just be as simple as some carbon build up.

 

Maybe a year ago. I looked in the throttle body today, and there's a little carbon build up. Nothing major though...

It's just weird how the rough idle starts as soon as it gets to operating temp and then smooths out after a few minutes...

 

At least it goes away lol

 

Ya, I know. It just really irks me when my jeep isn't running perfectly... I can't stop thinking about it til it's fixed lol

 

I hear ya. Sometimes I just have to tell myself that I bought a dodge, not a Honda. And that they are temperamental. But also a million times more fun.

Good luck. Wish I could help.