FLYCT

Sounds like tires flat spot after car sits parked for a while. I have an SC430 with Continental DWS tires that does this. If it sits for a few days and I pull on hyway the front steering wheel shakes. As I drive for several miles the shake dissipates to almost nothing. It only does this the first drive of the day.

I have another SC430 with Michelin Super Sport tires and that car is Smooth Smooth Smooth every time. Those tires never seem to flat spot.

Here is a link http://www.tirerack.com/tires/tirete....jsp?techid=42