I just bought a 2006 5.4L F-150 XLT three weeks ago. I have a high pitched squeel coming from my engine while the truck is driving down the road. It only occurs after the truck has sat through the night, with temperatures dropping below 30F. The noise will go away when I accelerate and decelerate, but comes back after I reach a coasting speed. The noise sometimes occurs during acceleration also. After the truck warms up (10-15 mins of driving), the noise will go away. The noise usually does not happen while the car is idling, only while driving. I know that it is not a belt or a pully, this is what the ford dealership originally thought that it was. Now that they have heard it, they are not sure what it is. It is with the dealership now. They are having a hard time diagnosing it, because they cant hear the noise while the truck is in park idling and it only lasts for a short period of time while driving.

If anyone has any ideas what this could possibly be, it would be greatly appreciated.

Thanks,

Erich
Wheatfield, NY

 

there are a lot of threads on here about this issue and the answer has been the alternator. it is a very common problem and i think all the older ones have it.

 

ask them to look at the electronic throttle. these trucks have a servo driven throttle. mine does the same thing. it operates kind of like a radio controlled car. servos hate cold weather. i was told this by a ford tech