I just purchased my 2007 a few months ago and it has 130k on the odo. When approaching highway speeds (70-75 mph) I am experiencing a significant steering wheel vibration that goes away when I let my foot off the gas, or when the drive train is not under load... going down a hill.. etc. The tires are Michelin and relatively new, and otherwise they feel balanced with no vibration. I would like some help determining where to look first. Thanks.