My 88' LeSabre is shaking bad!

I know almost nothing about diagnosing and fixing car problems, so I have come to the experts on here. I know I need to take my car in to a professional to fix it but I would like to know what is wrong with it before I do bring it in.

My car is a 1988 Buick LeSabre, it has about 141K miles on it and no real mechanical problems since I got it 2.5 years ago, until now. For the past week or two the car has been shaking really bad. Up to about 45mph it shakes side to side but above that it turns into a bad vibration. Forget about taking it over 70mph, it feels like the car is falling apart.

So, is it the wheels? front alignment? unbalanced tire maybe? Like I said, I know almost nothing. Thanks for any advice or suggestions.

I would have the wheels and tires looked at for damage first and then have them look at the suspention for looseness.

thanks

Could very well be bad CV joints[shafts].Why would you try to go 70MPH with a known vehicle malfunction?You are risking your life and others.Be safe,have it checked yesterday.

could be an out of round tire if it is shaking that badly jack the car up and give the tires a spin if you have a tire that has separated and is balloned out that could be your problem very easily check the easy stuff first