I usually average 19-21 in the city and 27 or better on the highway. On our return from the dragon my last fill up was in the evening and I did not refuel until 348.7 miles later and it took just a hair over 11 gallons for an avg of 31 mpg. I run sea foam though my tank about every 3-4 months, new Plugs thanks to Chuk and I am sure we blew some of the carbon out on the Hellbender... and always watch the tire pressure.