What's causing a misfire on our Ford C-Max?

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.

Asked on 8 June 2013 by GR, Wormit, Fife

Answered by Honest John
The old C-Max 2.0TDCI is geared at 35mph per 1000rpm in sixth, and doesn't pull well at 50mph in sixth. It could be that at the road speeds you are driving the DPF is not properly clearing or the EGR is clogging a bit. It's worth trying it on Shell V-Power Nitro+. That might clean the fuel system up a bit and allow cleaner running at low revs as well as well as improve fuel economy by as much as 6 per cent.
Similar questions
We have had a jerkiness/misfire problem on our 2008 Opel Zafira 1.8i. It happens at just the point the throttle is opening, i.e just as you have resistance on the accelerator. It’s particularly noticeable...
The emissions fix was done on my 2010 Volkswagen Golf 1.6 TDI in January 2017 and it now drives very differently. The DSG gearbox changes up into seventh gear much earlier than before (at around 40mph)...
I bought a Ford C-Max 1.6DCI Titanium in April 2011 and since its first service in December 2011 I have had acceleration problems. The main issue is when I am accelerating, when there is a flat spot with...
Related models
Neat styling. More practical than a Focus. Fine blend of ride comfort, handling and driver enjoyment. 1.6 TDCi emits 119g/km. High quality interior.

Value my car