Poorly Disco

For the first time since I bought it over 5 years ago my Disco has let me down. I'd just had the dog out for a walk when it refused to start. Fuel was not quite in the red so that's OK (ish) I thinks.
So I waited a few minutes and it started but with no real power. If I rev it a bit it will run but when I lift my foot off the go pedal slightly the engine stalls but will restart OK. I eventually limped home and looked under the bonnet - everything looks fine, nothing obviously amiss.
I'm thinking fuel starvation.
Any suggestions/advice would be welcome.

It's a 300tdi with 150k. Cam belt was changed last year

Possibly fuel filter.

worth changing the filter and bleeding it through ,if not possibly air getting in letting fuel drain back (lift pump or pipes)

Lift pump.

Replaced filter and lift pump - goes like stink now!

Ok......numpty question....

When you say 'lift pump' , is that the fuel pump? Or is it something else ???




I know, I know......... I can't help being thick !!!!

Yes it's the fuel pump, just buy a branded one as they can be taken to pieces to be cleaned if needed

Lift pump is on drivers side of engine block and has a little handle on it.

After leaving it for a day I came to start it yesterday and nothing Turns over ok but refuses to fire. Took the drain out of the sedimenter an nothing came out - is this normal?
Tried re-priming the system and still no joy. Any ideas?
Will try prime the system again this after.

Sedimenter should be full-diesel ideally,but maybe some water in bottom.I would undo with nut on top in future-plastic bit snaps easily.
As sedimenter was empty,suspect your fuel pipe joints to sender on boot floor-very prone to rusting out.
You need to fix air leaks and then prime with fuel up to injection pump-then she should start