I purchased a 2011 Mercedes-Benz ML350 from a used auto dealer. About 3 days after purchase lights started coming on in the dash. One is the Engine Light. Dealer said it could be because of the gasoline we put in the car. I explained we only use the one that is required and they reset the light, but it came back on again after a few days. I am taking it back to see what is going on. But am concerned after reading in this website from others saying they have the same issue and it's due to a problem with the balance shaft sprockets.