I heard this for the first time last weekend and then once again today. It occurs while I'm in Park or any gear for that matter and the gas pedal is not engaged. Its a high pitched whistle sound. As soon as I press the gas pedal it goes away and when I let off and the engine is back to idle, it starts again. Its only done it twice now but I have a feeling its going to become more common. Any ideas as to what it is?

 

Is your intake on tight? Check for a leak or loose bolt.

 

Mine too, but it goes away after a few seconds.

 

A small vacuum leak can make a whistling sound. When you press the gas pedal, manifold vacuum is reduced and the pitch of the whistling sound changes or it goes away altogether. Use a length of small-diameter vacuum hose as a listening aid. This will help you pinpoint the source of the sound.

 

I have the same prob on and off. And a new one...if you are crusing about 1800-2100 flat ground not right as you apply the gas you get a momentary whistle. So if you figure it out let me know.