At 80, 40 mpg is dead on with my experience. At 72-74, I would typically see 42 mpg. At 65, I will see mid 40's. At 62, I will get 46-47. At 55, I will break 50, but you can't safely travel at 55 mph on 70mph highways if traffic is heavy, nor do I often have the patience.
Wes
93K on my...