Hello everyone I’m new to the forum and eager to learn. I have a 2002 jeep liberty 3.7 that starting throwing P0300,P0302 and P0306 with a flashing check engine light. By doing a hard reset by disconnecting the battery it will throw the codes again with flashing check engine light on the third drive cycle start up.
Little back history. Started burning coolant and found passenger side head was cracked between two and four. Replaced head and started having this issue. During diagnosis, I have swapped injectors, coil packs, new plugs were installed with head replacement and replaced injector connectors. I’ve tried a different pcm with the same outcome. I have done some research and from what I have learned is a hard misfire will shut the injector driver module down on misfiring cylinders. Fuel pressure test good per Mitchell pro demand. I have also removed front timing cover to verify timing is correct. I have not performed a compression check to verify compression, but vehicle runs strong and good with no misfires during drive cycle one and two. This leads me to believe that it is not a mechanical issue. I was thinking wiring, but I’m kind of lost at the fact it’s on the third drive cycle start up each and every time. I am hoping that somebody can enlighten me with something that I don’t know or give me a direction to look. Thank you in advance.
Little back history. Started burning coolant and found passenger side head was cracked between two and four. Replaced head and started having this issue. During diagnosis, I have swapped injectors, coil packs, new plugs were installed with head replacement and replaced injector connectors. I’ve tried a different pcm with the same outcome. I have done some research and from what I have learned is a hard misfire will shut the injector driver module down on misfiring cylinders. Fuel pressure test good per Mitchell pro demand. I have also removed front timing cover to verify timing is correct. I have not performed a compression check to verify compression, but vehicle runs strong and good with no misfires during drive cycle one and two. This leads me to believe that it is not a mechanical issue. I was thinking wiring, but I’m kind of lost at the fact it’s on the third drive cycle start up each and every time. I am hoping that somebody can enlighten me with something that I don’t know or give me a direction to look. Thank you in advance.
