I recently purchased a new 2010 Honda Civic Sedan LX. Within a week I noticed the passenger seat was shaking. I brought it into the dealer and they informed me the right rear tire needed to be replaced and this was the probable cause for the passenger seat shaking.
This did not resolve the issue, and in addition now the driver seat is shaking and gets worse at highway speeds (45mph and higher). Took it back to dealer and they balanced tires twice now. Both times it has got worse, and now steering wheel column shakes and rattles when hitting bumps.
Dealer has informed me there is "nothing wrong" with my car and this is normal. When I test drove the car and drove it for first week, before right rear tire was replaced, the car drove smooth. I would have noticed the driver seat shaking and there were no rattling noises. They tell me it's just the tires picking up the road surface.
Please any input would be helpful as I have been unable to find anything on the net that tells me this is "normal". I find it hard to believe a new vehicle just starts having this issue and gets worse after each tire balance.
Has anyone else experienced this?

 

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