I have a 2002 3.0L Extended Cab and I have just noticed that I have a whistling sound that seems to be RPM based coming from some where. I have a flow master exhaust and chopped of one cat (so now I only have the first 3).

The sound seems to be coming from the back of my cab and doesn't matter what gear I'm in. It's hard to hear outside the vehicle due to the exhaust.

Any ideas?

 

Well exhaust flow changes with RPM, and Flywheel/flexplate changes with RPM
Fan belt and Cam Synchro also

Transmission and driveline changes with wheel speed

Wind noise changes with MPH and wind direction


Have someone hold a towel over tail pipe, engine idling, and see if you can hear an exhaust leak as pressure builds up

 

Could my fuel pump be making that sound? I tried crawling under it today but like i said it's kind of hard to hear from outside the cab

 

Fuel pump runs at constant RPM, once engine starts it is on until you turn off the key/engine, it doesn't cycle on and off.

 

Okay that's what I thought. could my torque converter bearing be whistling like that? It almost sounds like a turbo spool haha

 

Sure, could be that or input shaft/front pump, they all spin at engine RPM.
Transmission spins at driveshaft RPM

 

Found out the sound, it is coming from my subwoofer that is right behind my driver seat. I have never heard of that happening before (a whine that is RPM based coming through the speakers) but apparently it's common in after market radios and such.

Does anyone have a fix to this?