I have a 2006 650i cabriolet. Almost since new, the Service Engine Soon light periodically comes on. Often it comes on for maybe 50 miles after a new tank of gas, then eventually goes out. I try to use highest octane fuel, usually 91 in our area. I make sure I securely close the gas cap. The dealer recomended both. These do not seem to help. Any ideas?
Are you "topping off" the tank? I have read that if you overfill the tank beyond the point where the fuel pump's automatic shut-off activates that you will get the service engine light. This used to happen to me on my 1999 740i so now I just fill the 650 until the fuel shut-off at the pump (okay, maybe I squeeze in a bit more to get to a round number sometimes!) Good luck!
