Strange noise from the rear

[jem270]

I just got a 1997 4 door Grand Prix SE with the 3800 engine. When you get the speed up to about 30 mph, you get a noise that I can only compare to a coffee percolator. It is the same noise and cadence whether you are accelerating, cruising or decelerating. It is not a regular rhythm type sound like I would expect from a tire or rear end type problem. When you increase speed it does not get any louder either. It kind of sounds like wind buffeting noise. I looked briefly under and wiggled the muffler and what I believe is the charcoal canister in the driver side rear of vehicle but everything seemed tight. Any thoughts on this?

[richtazz]

sounds like a possible fuel pump getting noisy. It's the only thing in the rear of the car that wouldn't change cadence with speed.

[jem270]

Thanks. Good idea. I had not thought about that. I will get someone else to drive it and I will ride in the back seat and see if I can pinpoint the location as to left, center, or right. I thought it might be something flopping in the breeze.

[jem270]

I jacked up the right rear and found out the wheel was loose. The hub bearing was shot. I compared it to the other side and it was OK. I took it to a shop and they fixed it for $350.00. It seemed a little high but they said the hub had the built in ABS sensor and that made it high. I also did not have time to fool with it myself. Thanks for the help.

[ttintman]

before the fuelpump goes out it will whistle like a fast air leak in the tire.
may be something rattling inside the exhaust.