Thats the one thing that has been bugging me lately. Mainly on this forum, it always asks for average MPH. Well since my car doesn't do it for me, how am I supposed to know? But I DO want to know! Is there a formula, at the end of the tank - like calculating MPG, that I can use to figure this out? Any help would be appreciated. Thanks. Oh... my name is Eric btw. I'm new here.