2nd Gen Buzzing/Vibration sound under throttle

I have searched but have not found anything like what I am experiencing already posted.
When I start off under light / medium throttle I hear a buzzing like vibration sound, it isn't a vibration you feel but instead hear, it sounds like its coming from underneath, I have mounted a GoPro and my drone Runcam2 under the truck behind the transfer case, on the front bumper looking back, under the hood and I cannot isolate the sound and it sounds like its getting worse... at first it would buzz at start off and when it shifted gears, now at lower side street speeds (35-40mph) and if I am lightly feathering the throttle to simply keep above coasting speeds it will "buzz" continously. I thought it might be a loose heat shield, loose front skid plate but from what I can tell none of those are loose.
Has anybody had this? know of it? and have a resolution for it?

I will add, its not in the steering wheel, under the dash or inside the cab, you cannot feel it in the floor you can only hear the buzzing sound like the steel skid plate vibrating against the TRD aluminum plate (but both are tight as hell). I guess I can (and will, tomorrow) take the skid plates off and see if it still does it.

I hate noises because sooner or later they become problems and ANY help would be very much appreciated.