[WKYeti]

Could this be your Idle Air Control valve? You might try unbolting your throttle body and IAC and soaking them in kerosene and taking a toothbrush to them to get them squeeky clean again... Even if this isnt the culprit, its a good practice anyways once and a while on the 4.0s.

 

[WKYeti]

Well im definately no expert, but my wrangler was having trouble holding idle, and this was the cure. I hope this helps.

 

[WKYeti]

Great!