E53 diesel - idle dipping and fuel pressure issue

[Etwenty1 45]

My trusty E53 diesel has developed an irregular idle and the odd stall with injector error. Will restart and run fine immediately afterward. On a trip from bop to wairarapa it did this 3 times each time after a stop, open road seems ok. I have inpa but it’s the German version so difficult to translate errors. I am planning to change fuel filter but on vid the fuel pressure spikes up not down so thinking maybe an injector(s)? Any ideas please.

[dirtydoogle 383]

Check injection quantity values, chances are one or two are on the piss. If you're very lucky a new set of injector seat washers will help, but typically you will need a new injector. 

Diesel alltech and turbo sell them for around $400-420 I think 

They're not too difficult to replace.