Well my car has new tires on it, and 145,000 miles. When I bought it, it steered just fine, and had no vibration at all. Now above 45 mph, and up, there is a terrible vibration that occurs with acceleration. Its really bad at 60 mph plus, it about jars me to death, but when you let off the gas, it stops altogether....any ideas?

 

Sounds like a miss. Check plugs, plug wires, coil packs.

 

I wondered that, but its suck a violent shake, I mean it shakes the whole car! Like I said, only under acceleration, and its worse the faster you go...

 

Broken motor mount?

 

Check the steering linkage, mainly the rod ends. My roomates jeep would do the same thing and you had to stop the car to make it go away, but it ended up being the tires, but the mechanics were suggesting tie rod ends before we replaced the tires, just a thought.

 

thanks guys

 

My father purchased a 96 aurora too, his sat for a while, did the same thing, I drove it and it massaged my hands, but it wasn't as extreme as your describing. His problem was a bent rim.
take it back to the tire shop and have em check it, if they want to keep you as a customer theyshould be helpful.

 

It sounds like an intake manifold gasket gone bad, maybe. Check for minor coolant loss.

 

When I had the new tires put on, the rims were all true and straight, I was right there when they balanced them, and checked them....

Killer TA, what would that have to do with a bad vibration throughout the whole car? Its funny you say that, it smells like antifreeze sometimes, but I never see any leaking...

 

I just had the very same problem on my 1986 Cadillac and the intake gasket finally blew and coolant poored out. You might not see puddles because it may be burning up on the hot engine.

It was always losing just a tiny bit of coolant (no pulddles though) for about 2 years and always had the problem you're describing. It would ride fine under 50 but on the highway it rode like crap. After getting it fixed for $500+ it now rides fine. For 1-2 years I had no idea what it was.

They are 2 totally different cars but that sounds exactly like what mine did.