Make's whistling or metal grinding sound when im driving

[newtodsm97gst]

Make's whistling or metal grinding sound when im driving it always comes out whenever im on vac around 15-17 inhg, it goes away when i rev or let go the gas or i get off the 15-17 vac.. It sounds like eeeeeng... Metal grinding or whistling?

 

[MbFlash]

Whistling at a particular Vac HG reading might indicate a vacuum leak or device like purge solenoid.

You can use carb spray to isolate vacuum leak by taking note of the idle quality while spraying @ idle.
Keep an extinguisher handy and don't put your hands or face near the ignition system. I have seen oil leaking gems catch fire.
Grinding might be an idler pulley or brake, CV joint. ISC motor or most anything.

Cheers, Mbflash

If your turbo, it might be a impeller bearing @ boost time. not a good thing

 

[newtodsm97gst]

Whistling at a particular Vac HG reading might indicate a vacuum leak or device like purge solenoid.

You can use carb spray to isolate vacuum leak by taking note of the idle quality while spraying @ idle.
Keep an extinguisher handy and don't put your hands or face near the ignition system. I have seen oil leaking gems catch fire.
Grinding might be an idler pulley or brake, CV joint. ISC motor or most anything.

Cheers, Mbflash

If your turbo, it might be a impeller bearing @ boost time. not a good thing

it only happens on vac. which i think might be boost leak. I'll check that again.