[Dave]

I've had this car for about 9 months and recently it has started making humming and vibrating noises when I accelerate over 30 MPH. At about 50 MPH, if I take my foot off the gas, it will hum on and off as it loses speed and will continue to make these noises from anywhere over 30 MPH up until Interstate speeds.

Does anyone know what this could be? I have a couple of things in mind, but have never seen this problem. Thanks
The sound is similar to a train, maybe a little lower pitched. My first thoughts were Gear Box Fluid, check Transmission, and Tires, but it's too late to troubleshoot tonight.

 

[butwhatdoIknow]

Keep it simple. Try the tires first. Might be tread type. Swap tires around and see it the noise remains the same. Try slipping in the spare into the mix and see if the noise disappears. Might be one tire is starting to seperate.

When did the noise first appear.? Relate it to whatever was done to the car.

 

[ccourier512002]

You do not say what you have in mind. But more then likely to see what we say.

Vibrations. I would say have your tires rotated and balanced/look at to see if they are in good shape.

As far as hummimg between 30 to 70 is it more of a train sound. If it is that is ine way to tell of bad wheel bearings.

 

[Sarah <miyazaki75>]

Most likely is a wheel bearing, I change alot of those on that model of car. You gave a perfect description of what a bad wheel bearing does add sounds like.

 

[drvshaftdrew]

wheel bearing going out

 

[jpattonfamily]

wheel hub nown for these to go out

 

[Teddy K.]

does it go away when you drive on differant roads? but take is to a good tire shop w/ a "road force balancer" they are made by hunter enginering and they are the best for finding vibration. call around and see who in your area as one of machines. you pontiac dealer has one. a balance is around 39.99