Originally Posted by deutsch100

I'm pretty sure the check engine light can come on with continued use of 87 octane gasoline. Also, you're really only saving a couple of bucks per fillup, so it's not worth it! BMW requires a minimum rating of 91. The dealership said using lower than 91 does something to the oxygen sensor (don't know if it's true or not). My cousin put 87 fuel in her 325i for a while "trying" to save money, and the check engine light came on. The dealership charged her to reset it (even though she was under her new car warranty!)