Car Vibrations on 1997 Mazda Millenia

Hello my name is Keisha and I own a 1997 Mazda Millenia and my car vibrates vigorously when I accelerate pass 60mph but when I get up to 80mph, it stops. Also, there is vibration in the steering wheel as well. The vibration is very shaky and it seems like the car wants to fall apart. Also when braking, decelerating from like 80mph to 60mph or lower, the car kind of have a hard time slowing down with the vibrations. The vibrations are worst when braking. Please help!!!

Asked by for the 1997 Mazda Millenia
First thing is to have your tires rotated and balanced, Because a out of balance tire with vibrate at a certain MPH every time then have a shop check the brakes to see why its not slowing down properly and you can locate a shop here
2 more answers
He is right, also on mine, I had 2 bent rims. if they cant balance the wheels, check for warping of the rims
I had this problem on my Mazda Millenia. It ran perfectly fine until I reached 45mph. Then my steering wheel would shake violently. Believe it or not the problem turned out to be my front left caliper has seized up... Changed the caliper and now it runs like a champ!!!