my tahoe is whistling every time it shifts, not shure somthing to do with the evap system ?

 

I know this might sound dumb but, do you have any bluetooth radio transmitters where you connect your phone and it plays over the fm radio? cause I had the same sound when shifting, unplugged my bluetooth fm transmitter and figured out its just because the alternator is producing more volts causing the whine in the radio transmission from bluetooth to the radio