Questions and Answers
"Not My Wife's Vibration"
Q. After reading almost every article on your web site about Ford vehicles, I am hesitant to ask my question because it concerns a vibration. My 1997 Ford F-150 vibrates when idling and gets slightly worse when slowly accelerating.
After gaining speed the vibrations tend to ease up slightly. Even if I am in park and rev the engine it vibrates horribly. I recently took it to a shop and they checked the timing and a couple of other things but couldn't find the problem. They also mentioned something about this model Ford having a problem with the crankshaft after 70,000 miles. Well, mine has 91,000 miles currently.
I know you probably hate these "vibration" questions, but if you could help me I would drive to Minnesota just to shake your hand, and I'm in Texas!
Thanks for your help!
MattA. You didn't mention which engine you have in there, so I'm going to assume it is the 4.6 liter engine which is the most common.
Pull the spark plug wires off and see if there is water inside the spark plug wells. If there is, blow the water out and remove the spark plugs. Carefully look at the spark plugs for signs of "tracking." If "tracking" is present, there may be a fine, broken "pencil" line on the blue rings only and/or a thick smudgy series of continuous lines depending on how long the vehicle was operated while misfiring. These lines may feel like a crack if the fingernail is rubbed across the lines. If these track marks are present, you found the problem.
Replace the spark plugs and replace all eight of the Spark Plug Wires with new wires, Ford P/N F6PZ-12259-HC. Be sure to apply Silicone Grease and Dielectric Compound, Ford P/N D7AZ-19A331-A on the inside of all spark plug wire boots.
If I see you at my door I'll know I am correct.
Additional Information provided courtesy of ALLDATA
