I have had my 220d since June this year and it has now done 4.5 k.
I have just driven from Penzance to Leeds at 75mph on cruise control, 6th gear (1400 revs) & a/c on, virtually the whole distance averaging 62 mph over the journey. The tank average for this journey was 53.5 mpg. I had no problem with acceleration or anything else, this 410 mile journey was a dream to drive in 6:45, it was so smooth and comfortable I felt that I could have got back in the car and driven back to Penzance and still not felt tired on my arrival. On the whole drive only saw another 2 x IS cars underlining it's status as a car that is still relatively rare and noticeable on the road
From new the car is averaging 41.7 mpg and I do a mixture of town and motorway driving.
As far as I am aware the car has had no mods so why do I appear to be achieving a much higher than average mpg than most other drivers?