Tony
Letting off the gas with a shimmy is very strange.
Things to check are steering head bearings for one , if you have spokes, check for tightness, you should be able to take a screwdriver handle or the like and tap the spokes all around the wheel and hear them "ring" like a note. If you hear a dull thud, it's probably loose then. Check to see if you lost a wheel weight by the mark on the spoke nipple where the crimp on from the factory are mounted.
Hard to say just what it is over the internet but being an 07, they dealer should be taking care of it.