BMW Fault Code – Misfire Cylinder #5 – P1351 – M54 Engine
Hello, first able I would like to thank you for your knowledge and expertise that you give us readers every month. I enjoy reading about the car and learning it. I have a 2002 330ci with 85000 miles and this weekend service engine soon light came on. I unfortunately don’t have a peak code reader nor your code reader so I stopped by auto parts store to use their universal OBD II code reader. It said P1351-misfire cylinder 5 with fuel cut-off. As I learn more about this code, I came up with the following. My previous owner said that spark plugs were change @ 60,000 miles however he didn’t say ignition coils were changed at the same time. Do you think that if I changed my spark plugs and ignition coils would this problem will be OK?? I read that maybe leaking valve cover gasket might get into spark plugs or boots to cause this as well (I hope not). If that’s the case how long can I get away with just changing the coils, boots and plugs?? Is it ok for me to keep driving until I get this problem taken care of in near future? I am interested in your high-performance coils, do they come with warranty?
The miss-fire certainly could be ignition related. Since the park plugs were replaced recently, we would not immediately suspect an issue with the them. However, if the connector boots were not replaced, this could be a potential problem area as well as the possibility of oil leakage or a faulty coil.
As a first step, we would suggest that you pull all of the coils and boots and see if there appears to be oil in any of the spark plug tubes (oil on the boots). If there is, you do need to do a valve cover gasket. If #5 has oil, we may have found the source of the miss-fire. If there is no oil in #5, swap this coil and boot with another cylinder. Clear the codes, and see if the fault still comes up on #5 or if it moves to the new location of the coil and boot that was originally in #5 (and you have moved to another cylinder). If the fault moves with the coil, the coil or the boot are at fault. You can swap the boot and re-test or just replace all of the boots (they were likely not replaced when the spark plugs were done). If the fault still remains at the location of the suspect coil … then the coil may indeed be faulty. In this case, you can replace the one coil or take the opportunity to install the high performance coils (moderate power and economy increase).
The high performance coils do carry a 2-year warranty and they come with new boots.