5500lbs - 13mpg = 99 F250 SuperCrew Shortbed
2350lbs curb, 30mpg observed, 99 Sentra SE(SR20DE)
weight is basicly irrevelent for highway driving its all about the coefficent of aerodynamic drag the only thing weight has to do with is rolling resistance once the car is at speed. thats why when you have the same car say honda accord with the four cyl engine only gets slightly better fuel economy on the highway the the six cyl