My E class has been getting slower and slower so having read the various MAS/MAF posted I decided to get a new one from the Mercedes dealer. Fitted it last weekend and the car was better but still not as it should be. If I floor the accelarator it kicks down but will then change up at about 3,500 revs where before it would not change till around 4,500. Do you think I should take the MAS back and ask for a different one or are there other common problems I should check? Cheers, Peter.