Correct me if I'm wrong but I don't think that you can just drop in a new MAS. I think you have to reset the computer. Search and I'll think you'll find the answer. Did you ask the service advisor if you could purchase a MAS from Fastlane and have them install it. Remember what happened to my engine, I was running just a tad rich and it destroyed my cats. So, don't wait too long. There are many reasons why you could be running rich so if I were you I would have the dealer to do it. The dealer knows exactly what to do. Trust me, they have the experience in dealing with the MAS.