Rather than a sucking sound, I'm wondering if what you're hearing is actually a leak from an overpressurized exhaust rather than a vacuum source. Maybe the convertor or muffler is partially clogged...? My old Cutlass used to do this for many years before its convertor finally got completely plugged up.

Well, tonight, on the way home from work, I put her in neutral while crusing, let the engine go to a complete idle, revved the engine and was able to reproduce that sound.

I also sat in the garage, put it in neutral, and revved, also was able to reproduce the sound. I was able to hear it better in the garage, very odd sound. Like a high pitched sucking bong type whistle, would be the best way to describe it. And, I only hear it at the lowest part of the rev. The sound goes away once I get up to about 2000 RPMs.

Hope that helps.

I get this too. Its like Low whitsle, as if you were blowing into a bottle. It went away for the most part after I gutted the Airbox. the Air box is full of these tubes that create the whistle.

Airbox, you mean where the air filter is, etc.?

And thanks

If you're able to reproduce it in your garage.. just remove the accordian tube from the TB ( loosen 1 screw and pull out ).. if the noise persist then it'* elsewhere.. and if it'* from the intake you can hear it louder thru the TB.. try that.. more then likely it'* the intake.. but thats the easiest way to ensure its just that and nothing else