My brother has a 97 XJ with a 4.0 auto. This started happening and is getting worse! When on the trail it will start running rich , on the hard steep obstacles it will die and can't be started for about 20 minutes and runs rough, loads up and the exhuast smells like half burned fuel. It can be sitting running smooth, then just start a rough idle. It's now started doing this on the road but not as bad to point it dies and can't be started. Here's what we've replace. 2 TPSs, CPS. map sensor, air idle sensor, whole throttle body. Anybody got a suggestion, were out of ideas. thanks guys