my disco 2 was running a bit rough and would lose power every now and then, it also cut out a few times on idle and a couple as i was stopping at a junction.
i read up on this site about similar problems and have been purging the system now in morning by letting the pump go till it cuts, then starting and it starts better than ever, it seems to be running ok.
so any ideas on how the air might be getting in or staying in? cheers.

first step would be to replace the air bleed valve in the fuel filter head's rear wheel side pipe, google out WJN500110 ...if no joy we'll speak again

cool, cheers.