Weird sound coming from throttle body?

[colea]

So I've been hunting down this issue ever since I've owned my 04 3.9 (140k). cannot understand for the likfe of me why it sounds like this, but there's an insanely annoying resonance coming from the throttlebody. It happens on cold starts, especially when the AC is turned on, and randomly during normal driving (usually when the compressor cycles) at first I thought it was the AC, but after a new compressor and removing the belt and running it i found that to be false (a+ troubleshooting skills). The sound is coming from my cold air intake. When I remove the intake and run the car just open throttle body it gets WAY louder. Like Darth Vader is creeping up behind you. No whistle. No vacuum leak (that I know of. Idles ok) no cel. I'm lost. And annoyed. I really don't think it's a huge problem. But you get the kinda looks in the parking lot like you do with a squeaky belt. I'm 98% sure it's something to do with the throttlebody. I replaced the iac with little results. Cleaned tb, nothing. Scoured the forums and haven't found much other than some BMW guys with the same problem. Help? Here's a YouTube link
View: https://youtu.be/57a-ey4OOcw

 

[08GT500]

This actually has occurred before, there’s even a Ford TSB, one cause is Turbulent Airflow and casting inconsistency’s & replacing the TB with an aftermarket 65mm unit, lightly porting the Inlet of the Intake has alleviated it. But, Before you go there, know it can be a result of quite a few other issues, many- easy fixes...Can you please first elaborate on these?:
Did you do the 100K Plug change and perform a full Tuneup?
Have you hooked up a Scantool and searched thoroughly and checked if any Codes exist, or verify all your Monitors are in the “ready”
state, even without a CEL light ?
Any previous Codes?
Is the Car running a Stock Exhaust, or running other than a stock PCM Tune?
Is there any other aftermarket Parts on the Vehicle?
Ever perform a Compression Test on all Cylinders?
Did you replace the TB Gasket and verify there are no hairline Cracks in the TB’s Casting?
If you didn’t do this next item, please DO NOT until you know the extreme dangers associated with the process. There’s a MUCH SAFER ALTERNATIVE, without usage of a Flammable Gas. Just gaining info, here..
Did you do a leak detection around the TB with the Car idling, using Acetylene/Propane/Mapp Gas to see if the Idle RPM rises?
John

 

[08GT500]

Last Question: You did also say you ran the Car without the Serpentine belt on the Pulleys- so, the AC was shut off inside the Car, and no Pulleys were turning- correct?