Not sure if this has been discussed before or not. Long story short after about 15min of driving my rpms wont go past 2000. It starts spitting and sputtering. Had the same problem last summer. Then it stopped in the winter. Now that it's warmed back up the problem is back. I've replaced every sensor on The throttle body and then some. Maps, tps, iac, O2 sensors, Crankshaft sensor and temp sensor. Replaced the fuel pump. And can't get it to pull any codes. And the cat is gutted so I know its not clogged. Only when in drive. I'm out of ideas. 96 jeep xj 4.0 auto.

 

Mine's a 97, but I had a similar sounding problem that turned out to be a bad fuel injector. It'd start up OK from cold but after a few minutes I had wide open or idle (and not a very good idle).
How does it idle when hot? If it's off, you could just warm her up and unplug each injector in turn to see is you get a decent 5 cylinder idle.

 

thank you ill have to try that. The pig does idle a bit rough after she's warmed up.

 

all my injectors are good and I have spark on all cylibeers.

 

mine did that when the coil was dying. it had spark but upon inspection it was orange.