One day last week I took the xj a little faster down the interstate and when I pulled off my exit my Jeep stalled. Now it runs on a really low idle and shakes so bad that the whole exhaust is rattling when I am idleing..... It sounds like ***** and I have a major loss of power.......

I had the guys at both parts stores near me do the codes readings on it and they said..... That my #3 cylinder was misfiring, and that my air temp sensor was bad..... So I replaced the sensor and replaced all plugs wires and the distributor incuding the rotor..... No change. I did a poor mans fuel pump test and its fine, I notice however that when I pull off some air hoses and let more air into the 4.0 it won't stall, but still runs like hell.

I am wondering if anyone has any ideas? IAC maybe? Could it be in the exhaust????

WTF?!?!

 

do you still have a cyl 3 misfire

 

I haven't had a computer reading since. I litterally just changed the plugs, wires, distributor, and rotor.....so I dunno.

 

i see, i would get it checked and if it still it cyl 3 you might have a internal problem. or here is another test take some brake clean or intake cleaner and while its running spray the crap out of the intake where it mounts the head and listen for idle to change

 

Have codes CLEARED from computer, see what comes back and attack that code.

If cylinder 3 is still misfiring and you have already installed new plugs, plug wires, distributor cap, then the next things to suspect are the fuel injector and after that, the internal condition of the engine. (and in that order)

1. If you're using Bosch plugs, change them out for Champion. Ensure gap is .035

2. Swap the fuel injector from cylinder 3 with another cylinder. If the misfire follows to the cylinder with the original #3 fuel injector, replace that injector

3. Run a compression test on all cylinders. Dry, then wet. The compression spec. for the Jeep 4.0 engine is 120-150 psi, with no more than a 30 psi variation between cylinders.

Good luck and let us know what you find!