2001 F150 5.4. Plugs replaced a month or so ago. I did not drive the truck all weekend. then on the way to work this morning the truck started to stumble and hesitate. Check engine light came on and flashed and then went out...still stumbling. At a stop light the truck will shutter real bad. Put the truck in park and it all goes away??? Any idea?

 

Pull the codes.

 

Light has not come back on again.

 

there is a stored code retrieve it. Most likely p30x go to auto zone theyll do it free unless you live in california. Probably a bad coil. Did you replace the boots? dielectric grease? what kind of plugs?

 

I had an old Camaro with points ignition and this happened to me. Turns out there was oxidation on the points that gave it enough spark to idle, but when put in gear under load it would stumble and only go about 15MPH. Once the points were cleaned up it ran great.
I vote for a spark problem.

 

Being that this is a 4 year old thread, I would guess that the issue has been fixed or the truck has been sold.