Rear end noise/vibration
 

First of all the car is a 93 Bonneville SE. There has been a vibration coming from the rear of the car since last August when the fuel pump was replaced. When I first heard the noise, I took the car back to the shop that replaced the fuel pump and they told me it was a bushing in the rear suspension. It doesn't sound like a bushing to me and the noise is really getting annoying.

It does not make the noise all the time. It happens when I first start the car and it's idling and also when accelerating. It will occur intermittedly while driving, but stops once I let off the gas. Then I drive again normally and a few minutes later it comes back then goes away. Sometimes I don't hear it at all, other times I hear it the whole ride home from work. It started right after the fuel pump was replaced so I think it has something to do with that. Any ideas?

Frank