Audi Mileage Marathon
Audi kicked off its 4,800-mile, 17-state Mileage Marathon in New York city.

When Audi launched its first true SUV in 2007, the Q7 was noted to be luxurious, refined, but also thirsty. Since its debut, this premium large SUV has proven to be a capable, comfortable, family hauler that has loads of power but dismal fuel economy. Audi's new-for-2009 diesel-powered Q7 should solve that gripe. But diesel? When many automakers are focusing on hybrid and electric drive technology, why diesel? Diesel vehicles don't exactly have the greenest image or cleanest track record in this country. In fact, they've garnered a bad reputation as loud, coarse, and so dirty that they've been unable to meet the U.S.'s strict emissions requirements. Additionally, most people are only familiar with diesels found in heavy-duty pickups and big semi-trucks.

The Q7 TDI (turbodiesel injection), Audi's first diesel-powered vehicle to enter the U.S. market since the '80s, addresses all those problems. It's clean, quiet, and efficient. Audi is going to great lengths, literally, to banish diesel's dirty image with Q7. The automaker is on a mission to change America's mindset about diesel and its appetite for gasoline, and it's doing it one state at a time. To get the word out about clean-diesel technology, Audi embarked on a 4,800-mile, 17-state road trip through the U.S. to illustrate what it calls "the world's most successful efficiency technology."

I joined the Audi Mileage Marathon for the Chicago, Illinois, to Denver, Colorado, wave. And though on a map it looks like getting from point A to point B is a straight shot west and south, our group traveled south to Memphis, Tennessee, west through Dallas, Texas, then headed north to Amarillo, Texas, and eventually finished in Denver, Colorado. All told, we hit seven states during our 1,800-mile test drive. The challenge? Compete against other Q7 TDI testers to achieve the best fuel economy.

My previous road trip experiences from Chicago include several trips to Disney World and the Wisconsin Dells. Then, the family road-trip mobile was a 1993 blue and white striped Ford Econoline van with all the comforts of home: A jerry-rigged Nintendo system, a "bathroom," and a driver (Dad) hell-bent on getting there in only two stops.

This time around, things were a bit different. On this trip, I (thankfully) encountered far fewer mullets and (regrettably) much less cheese. Plus, I had the opportunity to test Q7 through the flat plains of the Midwest, around the plateaus in New Mexico, and over the mountains in Colorado.

The 2009 Q7 TDI is powered by a turbodiesel injected 221-horsepower 3.0-liter V6 paired to a 6-speed automatic transmission. Our tester came equipped with a voice-activated navigation system, rearview camera, adaptive cruise control, and a heated steering wheel--among other options. These weren't just any old Q7s, however. Our testers were painted two-tone silver and metallic charcoal and emblazoned with "TDI Power" decals and Mileage Marathon logos. We were hard to miss.