I have a 2003 Jeep liberty sport with 175k on it. it has a misfire cylinder 2 code. i replaced the plugs and coil packs on all 6 cylinders, noid light test on wires, compression check in all cylinders, everything works so far. i still have a check engine light for the misfire. i dont know if maybe the injector is bad for that cylinder, looks like it was recently replaced as with the other 6, or i have a leak of oil or air or coolant into that side either from the head gasket or intake gasket. the valve cover gaskets have been replaced recently as well.
You can try swapping the injector for cylinder 2 to another cylinder and see if the miss moves with the injector.
Tester
i guess ill give that a shot this weekend, front the looks of the fuel rail its gonna take a couple hours to remove. any further suggestions that i can do while i have all that undone appreciated as well! will update this weekend after i have finished swapping injectors
well I don’t know what to make of the news. first off my check engine light went off on Friday and stay off till today. because the check engine light went off and no codes came up when I tried to read them I did not swap out or replace my injector for number 2 cylinder. now today when my check engine light came on it read 8 codes, 201,352,351,300,301,302,837 all with a P0 in front of them. mainly cylinder 2 and 1 misfire and coil packs bad the one that gets me is the 837 which is a 4wheel drive circuit bad or something however my 4wheel drive is manual so I don’t see how I could have a faulty circuit since im the one that has to manually put in into 4wheel by hand. what I have done today since I read these codes is cleaned all my contacts for injectors and plugs, disconnected the negative terminal for about an hour while I did that, put the negative back on started it, no check engine light yet so im going to keep running it while I wait to see what happens. also note that the car still runs fine idles at 600 or so rpm maintains speed doesn’t feel sluggish, no roughness to it. any suggestions on what I can do or look for or test while I drive it to see if the check engine light comes on again and if so what codes it will throw at me this time? also with so many codes and no solutions yet could it be my pcm? hopefully not I think those are expensive. any help welcome, thanks!
Not sure what’s causing your problems but a bad PCM seems unlikely. If the vehicle is still functioning rather well, I’d bet the PCM isn’t the issue. Normally a bad PCM causes the vehicle to run like a bag of bolts it it runs at all.
Mike
after the batter was disc and then reconnected my check engine light is back on with 2 codes, p0837 and p0302 which are 4wheeldrive sensor/switch i believe and a misfire cylinder 2. i guess im going to have to replace the injector for cylinder 2 at this point. will update after i have completed that.
When I see this many stored faults it may be due to the customer unplugging connectors on the engine.
The first thing to consider is when does the misfire occur? It may be necessary to review the freeze frame data to determine this.
If the misfire occurs most of the time the ignition, compresion and injector must be checked.
However if the misfire only occurs on a cold start with a long crank time the fuel pump might not be holding pressure after shut down. The fuel rail on the 3.7/4.7 L engines are on an upward angle so after pressure loss the vapor in the fuel rail will collect at the front right side of the fuel rail. This will cause a brief cylinder #2 misfire during a cold start.
If this is the case the fuel pressure should be checked after shut down.