Hi all! A very long story short have replaced distributor cap, rotor, plugs, wires, cylinder head (old one was cracked fixed an issue was having before), all injectors (1999 style), TPS, MAP sensor, no vacuum leaks, good compression all cylinders, good spark etc. Now a misfire one cylinder 1 that started after head replacement. With the massive amounts of other problems Ive had with it I decided to just take it to a trusted mechanic cause I was tired of working on it. They said injector was bad so I replaced it, that one was a dud, so I had them replace it themselves, first one they got, didn't fix it, second one they tried, also didn't fix it but they said is 'better'. Its not. Ive been messing with this thing all winter as a project and cant for the life of me figure out why this thing never runs right. Currently there is a supposive good injector on the 1st cylinder and its fine now by what they say. The bad one has been switched to the 2nd and the issue has apparently been moved to that cylinder (doubtful) that injector has been replaced these last couple times with no improvement. Going to drive it and see if that is true when the CEL comes back on and report back, willing to bet its still on the 1st cylinder, cause how in the hell do you get 4 dud injectors? Does anybody have any idea at all what could be the issue with this thing? I am 100% lost and nobody else can seem to figure the thing out either. Thank you!!

 

Have you tested the injector harness for a short? I had a very similar issue to yours that was caused by a bad injector. But during my troubleshooting, I tested all of my injector connectors for a short because that could cause the PCM to tell the injector to fire 24/7. Again, in my case it was a bad injector but maybe in your case it's the harness. Below is a link to the thread I was on when troubleshooting mine.

https://www.cherokeeforum.com/f2/fau...2/#post3602937

 

shoot i done forgot about posting this haha, i have it figured out for the most part after lots of different injector brands and swapping around, no CEL for misfire in about 2 weeks of daily driving. I believe my fuel pump is about to die and is causing the issues i have now, the pump is getting loud and the thing bogs and runs like crap when you first start it until it warms up. Also hearing a knocking sound Now and hopefully its just flexplate bolts.

 

[QUOTE=owen.lox;3602977the thing bogs and runs like crap when you first start it until it warms up. Also hearing a knocking sound Now and hopefully its just flexplate bolts.[/QUOTE]
That happens with mismatched injectors. Put the OE back in.

 

They all match just not oem mopar ones