Lifetime average at 1538 miles is 16.6 mpg with a steady mix of low-speed DC highways 55-75 mph and country roads 40-50 mph, although at my last fill up (last night), I was pleasantly surprised by a predicted range of 578 miles (17.5 mpg). So it seems like it is still going up. I think my truck had a lot of idle time when I bought it -- probably to charge battery(?) Warmer weather also seems to make a difference, as does Top Tier 93 octane fuel (thank you, COSTCO). The donkey piss that was in the tank when I bought it I believe was the reason it was not using 8th gear. Tire pressure helps too. I'm running 42 psi cold // 47 hot. Trying to keep WOT brief and infrequent -- but I still feel like I'm driving like granny. It is all how you drive it. Coasting downhill to 85 to keep up momentum for the next uphill certainly helps too.