Mine seems highly variable, going from a low of 29 to a high of 35 or more under similar driving conditions. I just did 315 miles on less than 9 gallons. I thought the pump was cutting off to soon, as they sometimes do, so I ended up filling it to spilling over so it wasn't an underfill. I started at 5800 ft, went to just under 8000, than back to 5800 so there was plenty of up and down. I'm a bit confused. This isn't a very aerodynamic vehicle (not a complaint; that 's not what it's supposed to be) and the only thing I can figure is that sustained driving at speeds much over 65 mpg really kills mileage - even more than rough dirt roads. In my Mazda 65 mph or 85 mph yields an almost imperceptible difference in mpg. Anyone else have this experience - or other ideas? Brand of gas doesn't seem to be it.