Whining Noise from Intake Manifold- Please Help

[apexmoto]

I have a very loud whining noise coming from my intake manifold. I used a mechanics stethescope and it is the loudest coming from the intake manifold. I put it against the alternator and the noise did not seem as it was coming from there. Sounds like the high pitch electrical whine of a bad ground for the stereo system but I unplugged the radio and it still made the noise...so I know it is not that. Also when I rev the gas it starts to go away but as soon as I let go it comes back full force. This problem started a couple weeks ago and has gradually become worse. I have made no changes to the car for a few months. Any help would be greatly appreciated.

[pr240sx]

The alternator bearings.
Just to be sure, remove all the belts from the car and start it up and re chack the noise.
Could be also that your battery may be weak and the alternator is trying to charge it making that noise.

[apexmoto]

Thanks....I'll take the belts off and check that. I have a 4 month old Optima Yellow top and it is holding a good charge as I checked it with the voltometer.

[apexmoto]

Nope...not the alternator bearings...had a buddy look at it and he said it was the air regulator inside the manifold.

[pr240sx]

When I had a vaccum leak in the intake manifold.
I found it by dropping some water on every part where a gasket goes using a small tube and a funnel.
Have fun!!