ok when i get to about 55-60 mph my car starts to shake until about 90 mph then rides smooth.does this mean i need a balance or could it be something else.

 

check ur tires PSI. it should tell you on the side wall. my ride was doing this after i bought some new tires. i found out i was overinflated by about 10lbs!!! wooooooweeeee lucky they didnt pop!!! i fixed it, and it rides alot better now. OR it could be camber on ur car.

 

Could be your axles. Checking the tire pressure wouldnt hurt either.

 

how about tire wear? shredded tires can also exhibit symptoms like that. and don't forget an alignment either if you haven't had one in a while.

 

its prolly just tire wear or tire pressure as mentionned...4th gen preludes should have 32 psi on all four tires according to honda