I have a Ford C-Max 2.0 diesel (80,000 miles, around 53/54mpg), which has always been main dealer serviced by the book. It suits us well and goes very well except that, for over a year, it has suffered intermittent engine jolts very like a misfire. These vary from soft, hardly felt, to quite hard. The dealer has not been much help. After a diagnostic check that showed nothing electrical, all they could offer was that I should drive it hard for a while and avoid short trips. But I already do this. I have a bus pass, which I use for most short trips. Most of my mileage is open A-roads or motorways.