Hi Nick, I've been driving A6s for a number of years now and am presently driving a 2.l Ultra manual, non quattro with 14k on the clock. I've regularly followed mpg threads on various forums and am also conscious when I drive, of mpg. In fact I usually have the DIS on mpg when driving so that I can monitor it. I have also passed the advanced driving test and on non motorway roads always keep to the speed limit as today speed limits, in general, have been adjusted to suit relevant conditions. However I am not fixated by consumption figures in that I don't drive purely to see what the best mpg is.
I would like to make the following points:
On the new C7 Audis the DIS reading is much more accurate than on the C6 models.
My long term driving of these models would suggest that the idea of increased mpg after it has been run in is a load of bunkum. Now I know that many, many people would argue against that. My reasons for this are: 1) why would Audi sell you a car with 35 mpg when it could sell you one with a run in engine that does 40 mpg? especially in today's world of maximising economy. 2) The whole idea of a man made machine being more efficient after use really defies all sensible logic and physics. There is an argument that says that when an engine is new there are gaps between the piston rings and the chamber which, after use, get blocked up making it more efficient. Well in the 1970s Cortina that may well be true but in today's nanometrically designed engines? Doubtful, otherwise we'd still be running-in engines. This leads me to the conclusion that this may well have been true years ago but very unlikely nowadays. Unconvinced? then read this:
http://www.vwaudiforum.co.uk/forum/showthread.php/159200-So-cars-get-better-MPG-with-age-not-according-to-my-data
This was not my thread and not my car but it did support the above. I hope that the moderators on this forum don't mind me linking to a rival forum.
What I have found to affect the mileage most is the weather. In the winter months my mpg reduces, not massively but noticeably. And this is logical since wipers, heaters auxiliary heaters are in operation sometimes continually. Another thing, I notice that you turn your air con off to save fuel. I read a very interesting article by someone who had spent his whole life in Air Conditioning engineering and his conclusion was that you only save fuel up to the time that the Air Con and Engine are running at their normal operating temperatures and from then on there was no difference. What is important here is that if you turn off your Air Conditioning then the pressure in the pipes and joints is lessened to a considerable degree and wear is exacerbated leading to potential leaks later down the line - most importantly, repairing those leaks can be very expensive. I'll try and find that article. I ignore anything written by the Daily Mail or media of such ilk.
My mileage? The present A6 I have had since March so no cold weather yet. Varies between 55-60mpg on a 70 mile run on a busy A road. 50-55 on motorways. My drive select, which i regard as a gadget rather than a serious aid is always set to dynamic. It's a gadget because if you set the steering to comfort, after driving a few miles you get accustomed to the setting and then find that there is not much difference. The throttle response does work in a better manner and does mean that you have to press quite a lot harder on the throttle if you are in efficiency setting and hence works against itself!
Oh and regeneration. Well comes as a shock when it first happens as you think your car is overheating. It's fine when you get used to it. DPF problems? Not had one yet thank heaven but I bought my car with long journeys in mind.