Engine/Transmission (1998.5 - 2002) odd sound

[AWeik]

i just started to notice a howl/whistle (like blowing on the neck of a coke bottle) from 1250-1500 rpms during decel. i also heard it during heavy go pedal around 1800-2000rpm. is this a tell tale sign of LP or VP failure, or could it be my BHAF howling like some K&N FIPK's ive heard? id like to figure out what this noise is before it gets costly or if its even a problem..... any incite is greatly appreciated.

 

[GCULP]

swap the BHAF back to a stock one and see.