Engine vibrates at times.

[greg78]

Hi all. I just bought a 2008 expedition and noticed a “misfire” like in the engine but not all the time. It actually drives nice most of the time. Start driving at cold engine and it’s fine for about 20 minutes. Then a vibration, like a misfire, happens once in awhile and sometimes at a red light it’ll get really bad. Not all the time. I changed out the timing solenoids but no luck. It’s a 5.4L. Any help would be greatly appreciated.

 

[Trainmaster]

Of course the first thing I'd check are the coils and spark plugs. With the right computer you can find a "miss percent" of each cylinder. Do the plugs have more than 80,000 miles? If so, they're suspect for sure. With a spark breakdown as the engine heats up, I'd expect a boarder line coil.

Less likely causes would be a problem with cam phasers, though that's doubtful or a head gasket problem - another long shot.

Check out those coils, Greg, and welcome to the Forum. Let us know what you find.

 

[1997SCEBFEX]

see if there are any stored codes.

 

[deweysmith]

I have this too on my 2012. Been investigating a bit with FORScan. No codes, I can see an occasional misfire on one cylinder (but never one in particular) if I live stream the cylinder acceleration values.

I will keep poking around in my spare time, but yeah. It's not just you.