2000 Durango vibrating when when gas pedal is being pressed down

I'm at a loss, about a week ago my Durango started
vibrating when I am pushing down on the gas
pedal. It stops when I let off the gas and comes
right back when I press it again. The vibrating gets
worse the faster I go but again once I let off the
gas it stops and starts again when pressed. It can
be felt in the pedal, and the steering wheel. It feels
like the whole front end is vibrating. I went under
heath and checked the drive u joints but they dont
have any play in them at all. Most the things I think
of like, front axles, tires, bent rims, wouldnt make
sense unless the vibrating was constant right???

2000 Durango
4x4(front drive shaft was removed before I bought
it)
5.9L
152,000 miles