Hi I'm new to the forum. I have a serious problem I need help with. I got my xj 2 yrs ago and it ran great for about a year. Suddenly it ran hot. So, I got a new water pump, t-stat, and radiator cap. Problem solved. During g a test drive I noticed it was running like crap. Shutter spit sputter and backfire. On and off. It was a Dd so over time it got worse. Checked and had a leaky intake/exhaust manifold gasket. Put in a new and no change. Checked compression and fuel pressure and there good. Put in a new map sensor and no change. New plugs wires cap and rotor and no change. Checked CP's and it had bare wires showing so I replaced it. Now it won't hardly run at all. Any help would be greatly appreciated.

 

Fuel pressure? Maybe filter is getting clogged?

 

Good point. I'll try a new.one in the am. Thanks

 

oh I see you said fuel pressure was good.

 

Yeah I tested it after I changed my rail.

 

Cruiser 54 has an excellent diagnostics posting on this site for Renix system Cherokees, (and much of the data applies to newer generations also). His diagnostics will let you test additional components (like Idle control, throttle position, crank position, sensors), these can also result in your 89 XJ running rough. Also some great procedures in there for servicing and knowledgeable tips on how to install the parts correctly. Very worth while reading through and applying.

 

Thanks for the info.

 

In my signature below. Tips 1,3,4, and 5 first. Just do them.

Then we can proceed, if those don't cure it.

 

Well went through all 5 and still no change. Even went as far to second guess the cap rotor button plugs and wires and replaced them again. Still no change...

 

What is your current CPS output?

Tip 7.

 

The one I got yesterday was bad so I tool it back to advanced and got another from auto zone. Runs better but still spit sputter and back fire. Trys to clear up and goes back.

 

What's the output of the current one?

 

Not sure. I don't have anything to read with. Had a friend check all of em this morning. He said everything seemed normal.

 

Gotta know this....

 

As soon as i get it read I'll write back. Thanks