I have copied this from my post on another part of the forum.I've recently done a 301 mile trip with 298 of them on clear motorways and a small amount on dual carriageway and I averaged 33.64mpg (the trip computer showed a very accurate 34 mpg). I did not drive economicaly , on purpose, so as to get the worst case result. I would have got better mpg if I had keep my speed on the motorway down to about 65mph instead of 80mph.I have now averaged 29.49 mpg over 1114 miles. I had averaged, before this trip, 28.83 which is what I will expect to get from now on in normal driving. This, based on 28.83 mpg, means I am getting 17.63% less than the quoted 35 mpg.I always fill up to the brim, but I also keep very accurate mpg figures. I only fill up before a run as otherwise a fill up from the petrol station's cool tanks will expand out of the car's tank on a warm day.
Built date 5th December 2007 C-Max 2.0 Zetec Petrol Automatic