I have a 2004 TJ 2.4 with manual transmission, it started misfiring intermittently about a week ago. I changed the coil, plugs (the recommended NGK’s), plug wires, PCV valve, and air filter. The problem persisted so I took it to a local mechanic. He inspected all the wiring and fuel injector wiring and sent the fuel injectors to be rebuilt and cleaned. The Jeep ran great again for about 5 miles and the problem came back. He then replaced the purge solenoid because he said it was stuck open and malfunctioning. The Jeep ran great again...for about 3 miles and the problem returned. We swapped the purge solenoid again with a Mopar unit and the problem was still there. The Jeep will run fine and then misfire horribly and die at a stop. The check engine light will flash and occasionally throw a code for misfire most often for cylinder 3, but has thrown it for every cylinder. The mechanic checked the fuel pump and pressure at the rail, did a leak down test and a compression test. His next suggestion is replacing the ECM. Does this sound like the obvious next step or is there something else I should try first? I’m tired of throwing money and parts at the Jeep and nothing working.
