Bear in mind the C-Max tank is quite small compared to say, my last car, a Citroen Xsara Picasso. 53 Litres (11.5 Gal) compared to 60 litres (Nearly 13.5 gal) It means the fuel goes down more quickly, even though you may not be using any more fuel. For what it's worth, I'm getting a little over 44 average with my 2.0 TDCi. A bit down on 2.0HDi Pic (48 or so) which admittedly only had 90 BHP compared to the 136 of the C-Max!
Edited by: Big Budgie
2008 2.0 TDCi Zetec