Have you checked your tire pressure? Right after I bought it I noticed that my 4R was wandering lanes, and had a somewhat rigid ride.
I drove it for about two weeks, and then I thought maybe I should check the tire pressure, in case the dealer put a little too much in.
All my tires were at 44psi cold! Thanks Toyota dealer! I dropped them all to 34psi, and it rides and drives much better.
On the down side, I now get about 1mpg less than before.