Kia Troubleshooting Questions? Ask a Mechanic
Does it do this on smooth roads as well as bumpy roads?
Does it rock when driving straight ahead or only when taking curves?
Does it seem to be coming from the front, the rear, or both front and rear?
Have you tested the struts/shocks yet? If not, this needs to be done thru the simple bounce test. Push down hard at each corner nearest the wheels that you can. It should go down, back up and settle. If it goes down, up, down and up again, that strut/shock is worn