So I’ll preface this by saying I’m not a mechanic. I can follow instructions and I’ve got a decent idea of what I’m doing but am hoping to get some help from more experienced cherokee owners that have come across this before.

My son has a 1996 Jeep Cherokee that his grandfather gave him 3 years ago. 4.0L inline 6. Grandpa was the original owner. He drove it back from college recently and told me the CEL had come on. It also started running rough in idle but once while he’s driving it, it was smooth. At stops it runs a little rough again.

I took it to Autozone and put a code reader on it. It came back P0300 and P0301 (random misfire detected and cylinder 1 misfire detected). Knowing my father-in-law I figured it had never had a tune up and that he’d probably not run fuel injector cleaner through it, so I tried that first. I’ve run 4 bottles of injector cleaner through, and replaced the plugs, plug wires, and distributor cap. I reset the code after I changed out the plugs/wires/cap. The CEL went away for a few days but then returned with the same codes.

I’ve not done a compression test (nor do I have the gauges to do it). Should that be my next step? Or is there something else I should try next? Swap the injector to another cylinder and see if the problem follows? I read another thread on here, someone said they replaced the fuel filter and that solved the problem for them, but would rather not keep guessing if I can avoid it.

Thanks!

 

measuring the compression would rule in/out various critical issues, and would be the recommended course of fault finding action

As a cheap compression gauge is only about $30, that is what I would do

examine the injector wires harness, and swap injectors

 

I was chasing down some 300 codes on my 96. I threw parts at it trying to correct it. The solution for me was a new upstream o2 sensor, but it took me a long time and a lot of parts, and a lot of help from here before I got there (injectors, plugs, wires, cap, rotor, CPS, etc).

Good luck

 

Get a ligther and some gasoline. It is the quickest fix to a Jeep problem....

 

I didn't know that the '96 models were OBD-II compatible, I figured that they were still using the OBD-I system.

-Vince

 

Just take it out and clean it. Can of spray carb cleaner and a 12V battery. Just touch the connectors of the injector very briefly to open the gate (otherwise you could fry it).