My wife had a mechanic friend look at it and he said it was the aftermarket intake and that we should put the stocker on. I removed the intake completely and it still whistles with just the open TB. I'm new to GMs, as I have owned Dodges for the past 8 years. Is this a common issue? I was thinking maybe IAC valve (assuming it has one?). I played with all the vacuum lines going to the TB and none seemed to be loose or cracked. Not sure where to start. Noise does not go away even once the motor is warm, it is constant and does not seem to be effected by RPM.