Originally Posted by Diamondback
I don't record my fuel use but I get 400 on a tank pretty regular, and have never put more than 10.5 gallons in it. It has never averaged under 34.7 mpg combined and has run 43.4 on one fill up. Mine seems to get the best mileage at 69 mph. It is a DCT.
69 is way too high, try 35 mph in 6th gear for peak efficiency, although you really won't be getting anywhere in a hurry. 65 in 6th gear is right around 2400 rpm or so vs close to 2600 at 70 mph, ergo even going just 5 mph slower would be more efficient, but take a bit longer.