I have a s500 in the same year and mine does the exact same thing. It has been at the shop several time to try to fix the problem and there is nothing that they can do to get rid of it. My advice is not to buy the car you will regret it and may spend thousands of dollars to try to fix things that WILL go wrong with the car. That body style has been the most unreliable car that mercedes has made. Trust me you don't want to go down the same road i did.