My car recently developed a problem...when i reach a speed of approximately 60mph(or about 3rpm) and i let off the gas, the whole car vibrates quite a bit. As soon as i get back on the gas the car stops vibrating. I don't know too much about cars and was wondering could this be a problem with the differential?

How old are the U joints?

have you ever had the drive shaft balanced?

Any other noises?

How about the rear suspension bushings?

Personally I would think drive shaft or U joints.

Nate

Does it start to vibrate at higher speeds even when you have your foot on the gas?

what about the motor mounts? torque from acceleration might be keeping the motor still?? Just a guess........ Everytime my Z vibrated at around 60 MPH it was because of wheel balance. I've been told that Z cars are very sensative to wheel balance.

Could be a long list of things to be truthful.

U-joints, driveshaft, rear diff, diff mounts, mustache bar bushings, wheel bearings, tire, transmission mount, motor mount, .......

You will have to go with the obvious things like tires out of balance and go down the list of things it could be.

Thanks guys for giving me a place to start.