As the title says, my 1995 Cherokee 4.0 AW4 with 226,000 miles on it wont rev past 3000 rpm at idle or while driving.
I have tested the TPS which checks out, just replaced the IAC with a mopar part, checked both crank and cam sensors and both are good. I just replaced the fuel pump and getting 45-50 psi at all engine speeds, also just did the timing chain in hopes it would fix the issue incase the engine jumped a tooth. Lastly also replaced my O2 sensor a few months back so i dont believe that is the issue. Still facing the issue. At a complete loss on where to go now.

 

Plugs and wires? I had another car (91 Cavalier) that acted similarly with worn out spark plugs. Also check cap and rotor.

 

I actually had a rotor come apart on my 95 xj once. That was an interesting issue to diagnose.

 

It’s possible your cam and crank sensor signals are out of phase. A live data scan tool would give you the answer.


Check this 30 second video out

 

FIXED: after the engine was running so lean it messed up my O2 sensor so i cleaned it out with carb cleaner and it’s fixed. Also retarded the timing 1 tooth and it helped the acceleration of the car a lot. I don’t recommend doing that but it is an option. Check the O2 if you’re having similar issues!

 

Did it have any other symptoms? Rough idle or misfire?

 

It was struggling to gain rpm’s. Also after hitting 3000 rpm it would struggle at idle