Hi I have run a MAN diesel for the past 3 months with no problems, but about a month ago it started spluttering as if it is drawing air or missing. just took the fuel lines out no visible blockages. this problem was there 3 weeks ago but went away when the tank was topped up above half. the tank was at quarter before filing and now splutters even when full. ny suggestions please
Is the tank breather pipe clear?
I (many many moons ago ) had an identical problem and it was the tank breather pipe being blocked and creating a vaccum in the tank.
Hope that you get this sorted soon
and welcome to TruckNet UK
presume you’ve changed the filters 
Check to see if it has an in line filter (clear plastic, looks like a small bottle type container) it should have a removable gauze filter.
This sometimes gets overlooked when the truck is seviced, and if you leave it the truck will eventually come to a stop.
Hope this helps.
two things spring to mind, there could be a gauze filter in the feed pipe to the lift pump like dafs used to have, you can’t see it as it’s actually inside the bango coupling or failing that could be the lift pumps gone weak.
Rikki-UK:
Is the tank breather pipe clear?
I (many many moons ago ) had an identical problem and it was the tank breather pipe being blocked and creating a vaccum in the tank.
does it hiss if you take the fuel cap off when it’s having problems, if the breather is blocked it will do ! my old renault used to do that and have similar symptons !!
I created a new breather by drilling a small hole in the filler cap 
not too big or you might get diesel splashing up through !!
Denis F:
Rikki-UK:
Is the tank breather pipe clear?
I (many many moons ago ) had an identical problem and it was the tank breather pipe being blocked and creating a vaccum in the tank.does it hiss if you take the fuel cap off when it’s having problems, if the breather is blocked it will do ! my old renault used to do that and have similar symptons !!
I created a new breather by drilling a small hole in the filler cap
not too big or you might get diesel splashing up through !!
If it’s a 4series it will probs be paint chips peeling off the downpipe and blocking it, or sommat like, ours a 464 went through a real bad phase of it. I can’t remember how we cured it, but if you pm me I’ll give you the number of the lad who drove it.
Hi Guys thanks to all who replied about the fuel / missing problem turns out to be the gause in the filter bottle cheers anyway