Mike Joros
Member
01 Expedition 5.4L 257K mikes. Had this truck since new. I drive the vehicle monthly now, only use it for medium haul drives 4 hours one way. For past 3 years. I have had issue with the truck misfire occasionally for about 10 seconds when driving after one or more hours of highway driving. Once every 6 months it will misfire enough that it throws the code that designates "misfire on cylinder #3".
Over the past I have changed out all the plugs and all the coils(with dealer coils). Since that point changed plug and coil Number 3 additional two times... I even tried switching coils around to see if it would fail on a different cylinder(it does not only fails on cylinder #3) It seems to misfire less if I change out plug and coil #3… BUT just could be my imagination cuz I still have the same problem.
The wires to the coil and leading into the harness look fine. When I start it (cold) it runs and sounds perfect, it is only when driving at 70mph for a while before it starts to act up. I ruled out sticky valve because I feel it would do this more if engine was cold not hot.
Since the engine smoothes itself out after 10 seconds and will not happen again for the next 3 hours of the trip, I just keep kicking this can down the road waiting for some sort of revelation... or a catastrophic failure…
Has anyone came across such a problem?
Any help or insight would be appreciated.
Mike
Over the past I have changed out all the plugs and all the coils(with dealer coils). Since that point changed plug and coil Number 3 additional two times... I even tried switching coils around to see if it would fail on a different cylinder(it does not only fails on cylinder #3) It seems to misfire less if I change out plug and coil #3… BUT just could be my imagination cuz I still have the same problem.
The wires to the coil and leading into the harness look fine. When I start it (cold) it runs and sounds perfect, it is only when driving at 70mph for a while before it starts to act up. I ruled out sticky valve because I feel it would do this more if engine was cold not hot.
Since the engine smoothes itself out after 10 seconds and will not happen again for the next 3 hours of the trip, I just keep kicking this can down the road waiting for some sort of revelation... or a catastrophic failure…
Has anyone came across such a problem?
Any help or insight would be appreciated.
Mike