Corytrade
New Member
Hey guys. I posted this on a different jeep forum, but haven't gotten much help yet. Maybe I just went to the wrong set of experts 
I have been having an on and off issue with my 2005 Liberty (V6, automatic). It is actually a combination issue. About 1 in every 10 starts, it will take about 3 seconds of engine cranking for the car to start up. When this long engine start happens, the car will drive fine if I keep it below 2500 rpm. However, if I really give it some gas, right at about 2500 rpm, the engine will start what I can only describe as an intermittent cutoff. It will drop power for a fraction of a second, then resume, then drop power again and resume again. It makes this surging/jerking feeling, probably similar to if you were running out of gas (though I have never ran out of gas, so I don't truly know what that feels like). If I turn the car off, and turn it back on again, usually everything is fine. I can drive with no reservations. As I said, it will start fine a few times, then randomly go through this issue again.
When this happens, obviously the check engine light comes on. I had a buddy code read it for me, and it comes up with #4 misfire and cam sensor issue. I took the vehicle to the Jeep dealer, but I really don't trust them. They did a pressure test on the cylinders and #4 is pushing 90 psi, compared to the 150 psi (i think that was the number) of the other cylinders. They said I had a bad valve, and I need to re-machine the heads (only $2000!). I do not doubt that I have a low pressure cylinder. However, I do no think that bad valve is causing the problems I am having, and re-machining the heads wouldn't fix this issue. Since my problem is intermittent, I think it is more of an electronic issue, and not a mechanical one. Usually, by the 3rd or 4th clean start in a row, the check engine light goes off. This makes me believe even further it is an electrical issue, and that everything is operating well in between the bad starts/engine surging.
I recently realized this happened right after I changed the spark plugs from copper cores to bosch platinum +4's. After reading how the Liberty does not perform well with platinum plugs, I just switched back to copper cores last night. I doubt this was the issue the root of the issue, but I figured I might as well get back to OEM parts.
Thank you very much for any possible insight.
I have been having an on and off issue with my 2005 Liberty (V6, automatic). It is actually a combination issue. About 1 in every 10 starts, it will take about 3 seconds of engine cranking for the car to start up. When this long engine start happens, the car will drive fine if I keep it below 2500 rpm. However, if I really give it some gas, right at about 2500 rpm, the engine will start what I can only describe as an intermittent cutoff. It will drop power for a fraction of a second, then resume, then drop power again and resume again. It makes this surging/jerking feeling, probably similar to if you were running out of gas (though I have never ran out of gas, so I don't truly know what that feels like). If I turn the car off, and turn it back on again, usually everything is fine. I can drive with no reservations. As I said, it will start fine a few times, then randomly go through this issue again.
When this happens, obviously the check engine light comes on. I had a buddy code read it for me, and it comes up with #4 misfire and cam sensor issue. I took the vehicle to the Jeep dealer, but I really don't trust them. They did a pressure test on the cylinders and #4 is pushing 90 psi, compared to the 150 psi (i think that was the number) of the other cylinders. They said I had a bad valve, and I need to re-machine the heads (only $2000!). I do not doubt that I have a low pressure cylinder. However, I do no think that bad valve is causing the problems I am having, and re-machining the heads wouldn't fix this issue. Since my problem is intermittent, I think it is more of an electronic issue, and not a mechanical one. Usually, by the 3rd or 4th clean start in a row, the check engine light goes off. This makes me believe even further it is an electrical issue, and that everything is operating well in between the bad starts/engine surging.
I recently realized this happened right after I changed the spark plugs from copper cores to bosch platinum +4's. After reading how the Liberty does not perform well with platinum plugs, I just switched back to copper cores last night. I doubt this was the issue the root of the issue, but I figured I might as well get back to OEM parts.
Thank you very much for any possible insight.
