Hey ZJ owners, I know many of us have come across this same issue and I have read endless threads on recommendations for fixes and I have tried and tried to cure mine. ZJ picks its time to act up, sometimes it will run like a champ for about 30 minutes but then starts acting up, stalling and backfires, sputters. No check engine light, no codes with the three key turns except 1255, battery has been disconnected in the last 50 starts. This all started after trashing my trans in the mud and replacing it with a junkyard swap. Crankshaft sensor had to be replaced to get the jeep to start again after the install but has not run strong sense. Cap, rotor, plugs, wires, cam sensor, fuel pump, filter, new PCM, tps, cleaned throttle body, Seafoamed, fuel pressure is good, replaced O2 sensor, cut off the CAT. I have sprayed vacuum lines with carb cleaner looking for leaks, sprayed with soapy water looking for leaks. I have shaken wires and jiggled connections, tapped on the main fuse box, PCM, no changes when symptons are or are not present. I cannot locate anything that triggers the response. Has anyone cured their issues, found an area to look more into connections? PLEASE HELP MY POOR BEAST and my pocketbook....
Picked it up from Oreilly, my guess is your recommend the Mopar brand? Man, getting to that particular sensor s*cks to! I read your 12 step program Zee and thought I had it licked when I cleaned some connections but then about 10 miles out, the sputters and misfiring returned.
So after trying a few more things I have found that my fuel pressure at the rail was 34 psi, I replaced the fuel pump and filter again with a direct OEM replacement with no change. I pulled and capped the vacuum off of the fuel pressure regulator and the pressure jumped to 44 psi. At this time I figured I had it worked out but after driving it and getting up to running temp, it starts misfiring and popping all over again. Does this give anyone any ideas?
Thanks big, I am going to look at getting a mopar replacement. Did you happen to check your fuel pressure when you were having the issue or do you know if the sensor would throw that reading off? I am just puzzled that my pressure is still down. But maybe the misread if just affecting it.