The steering wheel vibrates all the time...even at idle, whether in neutral or drive! When I rev the engine in neutral there is no increase in vibration. Gets worse as vehicle speed increases. When I come away from a stop, within about 5-6 feet the front end will also shutter slightly. Just got new tires w/ balance, new shocks, and had the drivetrain checked (it was fine). The vehicle tracks straight at all speeds. Every mechanic that I know is stumped.