A FUEL-MILEAGE CHALLENGE: The 2015 Audi A3 TDI. “The goal? Albuquerque, New Mexico, to Coronado, California, on one tank of diesel. That’s a distance of 834 miles.”

Well, I got that kind of range out of the A8L TDI, which is a much bigger car. On the other hand, it also has a bigger tank.