Hi, I have a 2010 E350 cdi coupe that ever since I bought it in April has pinking. I know diesels are not supposed to pink, but when accelerating hard there is a distinct sound. The dealer says the car has all the latest software updates and has now covered 6500 miles. Performance is good and fuel economy is..well...ok....high 30's on a motorway run and low 30's in town....anyone else experience pinking?