qashquai 1.5 diesel intermittent fault

My 1.5 diesel is intermittently 'missing' when being driven. The car momentarily lurches as it 'misses' and then evens itself out again. This happens very frequently and the car has just been collected from the local Nissan dealership having had a new filter and battery fitted. Neither of these two items have solved the problem and I am wondering where to go from here?? (the car is a 2010 model).

The car has 40k miles on the clock and up till now has never been a problem. The car can be left ticking over on my driveway for a couple of minutes before it stalls completely but it will readily start again.I have noticed that the priming pump is always completely soft when checked - is this normal??

As a pensioner, I just can't afford to let the dealership continue to replace parts (at my expense). There are no fault codes on the diagnostic tests and they seem to be completely baffled.

Any ideas from out there please??????