I've had an '02 A4 Avant Quattro 3.0 for 2 years now, and I love the car, but I gotta say the fuel economy is that of an SUV according to the dash readout. Maybe 10mpg in the city and I'm lucky to break 21 on the highway. I just did a 300 mile drive through the Catskills and Adirondaks and came away with roughly 18mpg average, albeit I was doing 75mph most of the way.
I don't drive particularly aggressive, I know cars get their ideal economy between 55-65mph but is 10mph more plus the weight of Quattro and the thirst of a V6 really that inefficient?
Do you guys feel like your average MPG computer is accurate?
PS I have brand new tires, properly inflated and the car has no trouble codes etc.

 

It might not be apples to apples, but I have an '06 2.0T. In the last few months (Ottawa winter temps, snow tires, etc.) my trip comp has been reading from about 10.3 to 10.9 L/100km (21.5 to 22.8 mpg) but I keep a logbook and my calculations are consistently 1 L/100km (about 2 mpg) worse than the trip comp.

I drive pretty conservatively and at least 80% city.

So I guess my response to your questions are that the trip comp is a little optimistic (from other threads I think this is the consensus), and that your mileage does seem pretty poor but I'm not sure how much thirstier the 3.0L should be.

 

Other vehicle 2005 A4 3.0 quattro manual - I just did a return trip Vancouver, BC - Bellevue, WA and got around 26 mpg (US Gallons); highway driving a little above the speed limit

Your consumption seems very low, especially in the city. have you checked the standard things like air filter, wheel alignment, rubbing brakes.

 

The audi 6 cyl's are substsantially thirstier than the 1.8t or 2.0t, and the performance gain is really negligable, especially if you compare a 6 with a tip and a 4 with a manual. Now, if you want a really thirsty engine go for the 4.2 V8. it's a guzzler. Sorry, but I am a real fan of the Audi 4 cyl engines, probably the sweetest 4 bangers on the planet. I have found my dash read out reasonably accurate.

 

After basic tune up items like air filter etc, have the car VAG scanned. Check for proper O2 operation to be sure something like a vacuum leak is not causing fuel system to "dump fuel" as it can cause excessive consumption.