Greetings,
I am enthralled with my 2005 A6, but have an issue I hope to get insight on. When I purchased my A6 I was seeing about 11 MPG. My last 2 fill ups I been seeing a little over 8.5 MPG of premium fuel only. this is poor even by Luxo V8 standards. I have been tracking the fuel economy with an app I installed on my phone, so I have a steady fuel economy track record. I live in Chicago. I am not a lead footed driver. I doubt that a winter blend of gas would cause such a poor fuel economy showing. My drive has been almost exclusively local/city driving. Are there any issues or quirks specific to 4.2L V8 Audi's that is a major factor for the poor fuel economy? I expected a less than stellar fuel economy, but the poor fuel economy is exceeding my expectations. Any helpful insight, views, and suggestions will be deeply appreciated.

 

When was the last time you replaced O2 sensors, Spark Plugs and Wires?

Do you have any oil leaks in the spark plug wells?

 

--------------------------------------

Greetings,
I only had my car for about 6 Months. I don't seem to be losing oil. I did a little research and the general consensus seem to be with the O2 and/or Mass Air Flow (MAF) sensors. I will look into this. Thank your for your response and suggestion.

 

I suggest running a scan to look at the fuel trims and sensor readings. This will tell you a lot about whats happening. This car should get around 16-18 in town. I have been surprised by the poor fuel economy of the Audis. My 05 XJ8 gets 24 in town with its 300 hp V8.

 

Check the spark plugs if they are worn or not how many miles on the car and if everything else checks out fuel filter air filter and put some fuel cleaner in the car with a full tank and should help you with the mileage

 

Filling from the same fuel station with the same octane levels?

 

Follow up,
I checked my engine air filter. To sum it up IT WAS FILTHY!!! Dirt was falling off with just a light tap. I replaced it with a new air filter. I have not checked the fuel economy since replacing the filter, but the indications are looking promising. I am certain that the air filter was a main factor with my issue. I will keep you all apprised of my results. Thank you all for our suggestions to date. I also created a procedure for changing the engine air filter for my model year and engine size, seeing that I could not find a procedure that closely matched the procedure for my model year.