sounds like a turbo.
 

when i get the rpms up to about 4k when stopped or moving it sounds like a turbo under the hood. It sounds like its comin from right in front of me. Im guessing power steering pump. Also I had a leak in the PSP and put in new oil and it stopped.
Just wonderin if anyones had the same prob. thanks.

Its possible the bearings are going bad on one of the front end accessories. A vacuum leak will whistle. I would start by pulling the belt off and turning the pulleys by hand to check for bearing issues.

Had similiar issue. Turned out to be a water-pump bearing going out. Made a nice little whistle at any RPM, higher whistle the higher the RPM. I hope you figure it out! Lord knows sometimes I wanted to pull my hair out trying to figure it out lol.