The same thing happened with my 96 SL320, I had an inspection, once I got the car back from the dealer, the mileage dropped dramatically and I now smell gas when I start the car in the morning. The MIL does come on when the switch is turned on, but then goes out when the engine is running. What is an OVP relay and how much do they cost? Wouldn't this stuff show up on an ODB II car during inspection? I am really surprised at my decrease in mileage, the car runs wonderfully, maybe they adjusted my fuel type? because I was getting the MIL occasionally and they said it was because of bad gas? I always put 93 + in the car. If anyone has any ideas let me know.
Brian