I have and 01' f-150 supercrew 4.6l engine when i press the gas pedal the engine shudders, this also happens when the truck is in park.
when i stomp on the gas pedal it gets real bad. after driveing for 10 or 20 min the problem clears up quiet a bit. but if i turn it off and then back on its like hitting a reset button any ideas as to what might cause this. additionally this didn't start happeneing until after i picked my truck up from the body shop today before that the truck ran fine. The only thing the body shop did was lift a few dents on the doors and replace the hood.

 

If it was a misfire, then a Check Engine light would come on. If they replaced the hood, then I would look to see if something was not unplugged or something.

 

ok this morning the check engine light came on any ideas.

 

I've experienced a similar problem before. I had a spark plug wire that ended up resting against the exhaust manifold and created a hole in the boot of the plug. This caused the spark to jump to the manifold. Check to see if one of your wires/boots is resting on the exhaust manifold. If you park the car in a dark area and check under the hood you should see the spark jump when you rev the engine. That is, if it is what's wrong.

 

ok i figured it out this evening found that the no.1 and no.3 cylinders were miss fireing which was caused by the ignition coil pack for each cylinder being defective. I payed 50.99 for each coil at o'rielys auto parts. Autozone wanted 54.99 for each, these are pretty darn expensive but wow the difference it made.

 

I had the same problem with my 01 supercrew 5.4, I had a tuneup performed changed plugs and hoses, flush all the fluids, and it will run 200% better i also had 75000 miles at the time.