Sounds like my problem...Its smooth on the road and yeah when you hit a bump it vibrates.I know for sure my shocks and springs are gone.I took it to a few places today and they said you might as well recondition the steering rack .Mine sometimes makes creeking noise when you turn as well..so i fink we sorta have the smae problem..i wanna get it fixed asap coz i feels like its gonna fall apart when u hit a bump. hehehe