99 GA SE Engine Mount - Bad Vibration at High Speeds

My GA shakes bad at high speeds when the brake is applied. There is a minor vibration when the brake is not applied. Also, as I roll to a stop, I can feel the car rock.

The wheels have been rotated and balanced and the rotors have been turned.

I jacked the front end up and rand the wheels at idle speed to see if the tires appeared out of round - no visual evidence. But when I applied the brake, the engine dropped toward the firewall at least an inch or more. This appears to be excessive to me and my theory is the motor mount(s) are the reason. Any thoughts?

Do you have any flat spots in the tires

Do you have any flat spots in the tires


No. Tires appear to be fine and the vibration does not change after sveral rotation/balance cycles.

mounts, and warped rotors are my guess.

Does it vibrate or does the vibration change during acceleration? If so I'd say wheel bearing are the problem but if it doesn't then motor mounts are probably your problem. As for what I'll say it is "wheel bearings" for $100 alex...lol

I wouldn't think that the motor should move, i also have a 99 grand am and have never seen anything like that. But as far as the vibrations, i know mine made a lot of noise and it ended up being the wheel bearing, but the noise did not just happen when the breaks were applyed, although when accelerating the noise increased. So i would give that a shot they are realitivitly easy to change, i finished mine in about an hour.

Another thought for all you grand am owners, the intake manifold gasket is known to leak anti-freeze which could leak into the motor oil and burn up the motor, I am also at the moment experiencing problems with the computer system which is causing my tranny to slip and my gauges to get messed up. Just wanted to offer a little fyi for future grand am owners.

Also anyone out there own a new jeep wrangler, i know someone considering one and i was wondering if anyone knew of any problems that seemed to be occuring on them?

I had the same problems with my 99 Grand Am. The faster I would go the more the car would vibrate, shake and make awful noises. We had the breaks/rotors replaces and it lessened the noise a little but it was still there. It wasn't until we replaced the wheel bearing that the noise and vibration/shimmying went away.