We traded balmy Dallas weather for cold rain in Amarillo and sleet that bordered on snow in Denver. During the last leg of the trip, my drive partner and I averaged 26.2 mpg for a four-day, 1,800-mile average of 25.8 mpg. Granted, most of our driving was done on the highway, but considering Q7's hefty size and weight and the terrain changes we faced, 25.8 mpg is no small feat. By contrast, Consumer Guide's long-term Q7 with the 280-horsepower 3.6-liter V6 averaged just 17.4 mpg during its 12,953-mile test.
 
Even more impressive were the fuel economy numbers achieved by the TDIs that aren't headed for U.S. dealerships: The lone A3 averaged 45.8 mpg, A4's fuel economy champion averaged 46.2 mpg, and the winner of the Q5 contest scored 37.3 mpg. 

Despite these hybrid-rivaling figures, Audi may have an uphill climb ahead of it (and not just out of the Rockies) when it comes to reversing years of negative thought surrounding diesel-fueled cars in America. Though the Q7 TDI is clean, quiet, and fuel-frugal, there are other hurdles facing clean-diesel technology. When Audi's new TDI goes on sale in January, cost will be an issue--both up front and throughout the life of the car. Official prices haven't been released, but we expect the diesel option to add approximately $2,000 to your bottom line. Fuel will cost you, too. During our travels, diesel was typically around 60 cents higher per gallon than regular fuel. Since gasoline-powered Q7s require premium fuel, the difference isn't so drastic, but still noticeable enough to possibly deter penny-pinching consumers.

However, this trip proved that Audi has piqued people's interests when it comes to diesel. If the warm reception we received throughout the Midwest is any indication, Americans are ready and willing to give diesel another try.