Tesoro Petroleum
Premium Unleaded causes noticeably reduced mileage
We've been filling up here for two months, our car takes premium. It can run on regular, but at reduced MPG. We only tried because the station was close and 15c/gal cheaper. Usually we get 270-300 mi/tank before refill. The 3 tanks of "premium" here only got 200-220 miles before refill. ...