So thursday i noticed that when you really get on the gas in 3 - 6th gear @ about 2500 rpms the front passenger side of the car vibrates really bad but if you let off the gas it drives just fine, if i accelerate more modestly it doesn't vibrate at all. but when you hit the brakes it makes a thumping noise in proportion to the speed im going. after letting off the brakes the noise is still there but not as bad........ any ideas????? i took it to firestone and they said its internal in the engine or transmission..... I think they are full of crap considering it drives smoothly and the enging and transmission are not in the wheel well (last time i checked)

 

It's not related to the to the power train, it's more than likely a axle going bad.

 

changed the CV axles and still vibrated under heavy acceleration in 4th 5th and 6th... could it be that the clutch is worn unevenly and grabbing like **** under full power or possibly something in the passenger side suspension...i checked everything when i tore it apart and nothing was broken or worn