I am just about to buy a 2004 F150 Supercrew with the 5.4l... Only thing holding me back is this squealing / whining noise, it is VERY high pitched and it definitely sounds like its linked to the gas pedal/throttle.

It happens when I barely press the gas pedal down, like where you might hold your foot while just cruising.. if I press the gas harder, it goes away....let off the pedal, it goes away. It seems like one certain point in the gas pedal/throttle makes the noise happen.



Thanks - Darren

 

Look down this section, kick back and read the 'whistle problem log'

 

I have an 02 4.6L and my truck did exactly what you are describing after it sat without being run for about a month (bad I know). I finally figured out the problem was coming from the tensioner pulley bearing. I pulled it apart and found that there was no grease in it, so I soaked it in rubbing alcohol, packed it with fresh grease and put it back in the truck. It still whines a little bit, but I don't notice it unless it's night time and I've got the music off and the windows up, which is almost never. As far as I'm concerned, the problem is solved.

The sound was pretty strange though. It was kind of an eery, hollow, whistling noise that changed pitch with the engine RPMs. Take your serpentine belt off and turn the tensioner pulley by hand. While you're in there you might as well feel all the other pulleys for roughness, too. Good luck.

 

thanks for the info

 

If you haven't already checked the pulleys, I forgot to say you can just start the truck without the belt on and you'll know instantly if it's related to a pulley .