I’m new to the forum and just picked up a 2011 A4 quatro premium tiptronic a few months ago. I fill up with 92 octane or higher and the gas consumption is poor. There are no noticeable signs that there is anything wrong with the car. I drive equally on the highway and city streets (50-50). I'm averaging around 350km per tank and its a 64L tank. This converts to 5.5km/L or 18.18L/100km or 12.94mpg. I am not pushing the car at all. What type of fuel consumption are you getting out of your A4 (B8) and what year is the car? This appears to be a problem, would you agree?

 

Either your car has a serious problem, or you've got your math wrong.

I'm getting about 27mpg mix city/hwy... so a tank should last me 460 miles or 740km.

With Quattro you'll get slightly lower numbers.

 

Your calculation assumes that you're using a FULL tank of guess every 350KM, but I assume you're filling up before the tank is fully depleted. You need to calculate the MPG based on the miles driven between fill-ups divided by the # of liters of you actually put in each tank. You may be interested in this link:

http://www.fuelly.com/car/audi/a4%20quattro