My last tank was my first sub 40mpg. I hit 39.5. WIth the snowstorm and the cold temps I knew I would take a hit. I also had been going to pump up the tires for the last 3 weeks.
Well after filling the tank I add air to the tires. At cold they were in the low to mid 20psi. Worse than I realized. I brought them up to 42psi.
WIth 40 miles on this tank, warmer temps (but certainly not summertime), and better air pressure in tires, I am at 52 mpg.
It will be interesting to see how this tank progresses.
Mike