Crazy idle
 

K so I was having stall issues. I looked here and saw it was a cps. No worries all done. So it starts misfiring real bad. Now it won't rev over 2000 it's all choppy as it runs I will b changing coil pack and plugs. Any other ideas? O it also kicked out lots of carbon from tailpipe as well.
It is a 2001 Cherokee inline 6 /4.0

Now I changed the coil pack and the plugs still misfiring without producing a code

Verify fuel pressure. Must be done with a gauge. Some big box parts store will rent you this gauge; call around.

For your 01, you should have 49 psi, plus or minus 5 psi.

You must rule fuel pressure in or out early in the troubleshooting process.

Good luck and let us know what you find!

So was going to go through wires to see if computer was bad. Now my cel is blinking. Lovely. So new cc it is.

A blinking CEL indicates a serious misfire, which if ignored, will destroy your catalytic converter. But if you catch it early enough, you may be okay.

Gotta get the codes with a scantool, or a code reader. Post them here for comment.

The codes are the most valuable tool you have in finding this problem.

Not getting codes. Did the key game and a scan tool had a boy hook up a snapon scanner he uses at work. He's a mechanic so I figured his scanner would do the trick and I get not a single code.

if you not getting any code there is a problem should of got at least 55 end of test some readers will not work on xjs search it

He has used the scanner on many xj. So I am confident in his scanner. Really starting to think it's the computer. Maybe the mystery short I have killed it. Or maybe it is just a jerk and likes screwing with me. My xj has a sick sence of humor.

verry positive it is the computer
checked out it must b replaced

Nope not the computer
Gerr wtf
No code either. Still misfiring or something. Not sure what the he'll it could be. Got to love throwing $$ at a problem that has no name and no code no real answer. This is up to 500 with no fix

My iac did something similar once and never threw a code, I cleaned it and all was good

Gonna clean throttle body today an iac.
Any wat the crazy idle is more of a stuffer now. It foes it randomly.
What does a bad fule filter act like

was any repair on modifactions done right b4 this started

Check fuel pressure WITH A GAUGE. Otherwise, you're guessing on fuel delivery.

No I didn't do anything