Hey everyone,

I just picked up a 2002 F150 7700 with 50000 miles, 5.4, 4x4 (my first Ford truck). I have noticed a vibration or jerking that happens at speeds from 30-50 mph under light acceleration. If I give it more gas and the trans downshifts the jerking goes away. The trans shifts fine also. The fuel filter was replaced about a month ago. This is really annoying and I was hoping anyone could shed some light on what the problem is before I bring it in to the dealer. Dont really have any money to spend on it right now but I do have an extended warranty on it.

Any help is appreciated,

Jason

 

My first thought is a driveshaft universal joint or a lowlevel miss caused by a bad COP.

 

Thanks for ideas. I thought it might be a bad coil also that is only showing up under part throttle in higher gears.

 

Even though it "only" has 50k on it, I'd change the spark plugs. Motorcraft, no antiseize, 28 ft/lb. Dielectric grease in the coil boots.

 

Thanks for the help. It ended up being a bad coil pack. Replaced the plugs also. It still had the originals.