on going problem,the disovery started spluttering and came to a standstill. I replaced the lift pump worked fine for two weeks then the same problem occured.replaced the fuel pump worked fine for two weeks then the same again.cut the fuel pipe and fed the engine direct to a can that was fine so i then replaced the line back to the tank.worked fine but you guessed two weeks later the same problem any ideas ?

Sediment or blocked, fuel tank pick up blocked, or air being drawn in down stream from the pump possibly?

check ur bleed off rail for leaks mine did this.... Took me ages to find it i had a tiny leak on no. 3 cyl where the pipe had gone hard.... Slowly let air in.... Cut out and after getting it started again a few days later it happen again... Changed the pipes and all is good now