I do 70 motorway miles per day and mostly cruise at 65-70 ( honestly )
Currently getting 27-28, upto 30-31 on longer runs, but that seems to be on trips that are 100miles plus by which point i have usually reached the local town i'm travelling to dropping the consumption back to 27-28! bummer.
I have have had my 3.0 TDI for 11 months and 10,000 miles now and the avaerage over that time is 25.6mpg- not bad for saying I drive it like a GTI
On a round trip of 500 miles to Wales to our caravan (including lots of overtaking) I get 28mpg but the 2 miles into town during the week to pick up my good lady from te shops kills my MPG so it could be better- thing is- I have a Jag as well but the Terg is much much more fun - I burned off a Range Rover Sport 4.2 SC at the lights last week (he was not trying or he knew I had more torques)
I love it...
Trip computer says 27mpg round town but a brim test reveals 25. Long run 200 miles to South Wales on Motorway & A roads shows 30mpg on computer but closer to 28 on brim test. Only 6600 miles since March & getting better all the time. Would only do 25 on a long run when I first got her. A/C nearly always on, brisk driving but not being silly...
I always stop on the click, mind. Only because I don't have the patience to stand there packing it in until I can see it in the neck of the filler. La Wurzelina can't stand it either because she can't leave the odd pennies on the pump; she has to round it off!
Before i had the car chipped i was averaging probably 25-27mpg then i had a chip fitted which made immediate improvement to both tork and mpg.
However whilst the engine was fine the gearbox change became aggressive so i had the chip removed and the engine re-mapped. I now have a great drive and trip computer shows just under 31mpg average consumption or around 500 miles to a tank. considering most of my driving is local / around London that will do for me.