Humming Noise/vibration Throughout Cab

[gilroy222]

I have a 2000 gmc sierra 5.3 with 200k on it. I have a CAI, true dual exhaust and a custom tune. Recently when i've been trying out the tune and flooring it at around 70mph it will pick up to 80 and start to get this really loud vibration/hum going on. Stops once i let off and every once in awhile if im cruising around 50, i will give it some gas, just enough to accelerate but not downshift, and i'll get the same type of noise but it's a LOT quieter. Any advice is appreciated.

[gilroy222]

EDIT: you can also feel this "noise" even at the lower speed.

[Silverado4x4]

Tough to say without hearing or fealing it but your "U" joints might be on the way out, they will make the noise your saying also a driveshaft out of balance will do it too.