1998 National Speed Limit?

[gto78]

I noticed on my 350Z there's a much wider range of driveability and speed vs mpg. I can drive at 55mph and get approximately 33 mpg, and at 80 mph I'll get around 25 mpg. So I normally just set the cruise for 74 or whatever is closest to the traffic so I don't have to keep accelerating/decelerating etc.

I think the car and the truck are showing the same speed breaking point at which the mileage drops except the truck magnifies it and makes it much more obvious. The design of the 350z is not so much sleek as it is more designed to sort of punch a hole in the air and lift it (the "hole") up high enough for the rest of the car to drive through.