I usually don't trust averages on one tank of gas, too many variables. When I drove my Audi back to Detroit MI from Sacramento CA in 2013, the onboard computer consistently said 32 mpg. I took the road less traveled to Denver, then I80 to I94. I kept every gas receipt (including $4.69 per gallon just outside Yosemite), and in 4,200 miles, the real world average was 31.995. Included; a few pictures from a really great trip done on the cheap.