Last fall my '99 OBW seemed to suddenly suffer a gas mileage drop. At the time I though it might be the switch to winter fuel, and my feelings were more or less confirmed when I got a tank of apparent summer fuel a month or so ago.
In the winter, generally 300-325 miles per tank. Now, closer to 380-400. (I don't count tanks where I was driving on snowy roads)
Do I have a bad sensor or something?
-John O