[GingisK]

FYI, my *older* car gets better fuel economy at 75 than it does at 55, due to gearing and powerband. A lot of other cars are that way too.

That simply cannot be true. Air drag increases with the cube of the velocity. Older cars were rarely designed to reduce drag.

[Spktyr]

Next time you are in Dallas, feel free to come visit. The fact remains that at 75mph, the XJ6 is getting 24mpg, and at 55 it gets 19-20.