why doe my truck have a shake to it at around 55 until the engine warms up? on 2007 Ford F-150

When i get up around 55 mph my truck has a shake in the front end until the engine warms up and it seems like it misses at that speed until the engine warms up.

by in Hopkinsville, KY on February 08, 2013
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2 answers 3 comments
ANSWER by , February 08, 2013
Misfire,When the vehcile is under load a coil demands on a sparkplug are greater so your you are looking at a misfire, you are equipt with a COP (coil on plug),Also because you are a F 150 go to the passenger side at the rear of the sparkplug area look for coolant leaking into the sparkplug chambers that also causes misfire, Above all else it is time for a tune, will it fix this you bet, unless you like going to gas station
COMMENT by , February 08, 2013
thanks for your quick response. What would cause coolant to leak into the spark plug chamber?
COMMENT by , February 08, 2013
Bad design,that my opinion,but get this check because when you get these small misfire its either coolant contamination or a sparkplug loosened in the camber ready to blow out, and the repair for a rethread on the cylinder head is one arm and one leg and one eye,
ANSWER by , February 08, 2013
could be serveral issues with water in plug hole,heater hose above it leaking. thats most likely why it runs rough cold. when water dries the misfire is gone. have cooling system pressure tested to determine leak and that might repair misfie also
COMMENT by , February 09, 2013
I take it in to the dealer Thursday to be fixed. I had the computer put on it and it shows a cylinder #4 misfire