You are cheated by the gas station you use before
Road condition are different: wind, ascend, altitude.
speed you drive, patern of accelaration, load, tire tread. tire pressure, AC on/off, window down.
Recent repair, maintainace work improve effeciency.
Miscalculated before, my 88 accord had 37 mpg highway.
Odometer malfunction (or become accurate now).
Your memory does not serve well.
Road condition are different: wind, ascend, altitude.
speed you drive, patern of accelaration, load, tire tread. tire pressure, AC on/off, window down.
Recent repair, maintainace work improve effeciency.
Miscalculated before, my 88 accord had 37 mpg highway.
Odometer malfunction (or become accurate now).
Your memory does not serve well.