My father owns a 2003 F-150 and when he got in his truck a few mornings ago and started to leave his house the accelerator pedal got stuck all the way down. Luckily the truck was parked on a sheet of ice so he didn't go anywhere. It happened again on his way to his mechanic. I asked if his floor mats where in the way and he claimed no. We live in the Northeast and it was pretty cold during the night so he was wondering if somthing could of gotten frozen in there. His mechanic couldn't find anything wrong with it either. Anybody had any similar problems or ideas on what happened?

 

Just start checking the throttle linkage while it is still cold. Pretty much the same conditions as when it happened. Check it too with the key in the ON position but not started. Wouldn't want to blow the engine with it revving to max while sitting still.
Press the pedal down all the way while someone is looking under the hood. Make sure all parts move freely and don't delay in releasing. The mechanic may have been checking after the engine has warmed up and whatever caused it may have freed up.You will have to remove the plastic cowling over the intake to get a good view but not a big deal.

ANyone else have ideas?

 

Please check the throttle body as well. If that has not been cleaned in a while, maybe it is time to look at doing that.

 

Also for a 2003, its doubtful, but you never know...check the backside of the pedal for any cracks, breakage or binding.