veg perished pump causing stalling?

[kernow_joe]

right its not an xud but still an idi diesel so hoping I may be able to get some good input.

car in question is my suzuki sj and the engine is a isuzu 1.7td (4ee1) from a vauxhall cavalier.

bit of history picked up the truck and was running, drove on and off the trailer, after sitting idling fr a minute it cut out, shortly after I found the snorkel had rather a lot of water in it, but I don't think any entered the engine, as does run fine now when it goes.

found the fuel pipe from the lift pump had split so replaced/ fixeded them all up, now it will run for a few minutes lovely and then stall as if starving from fuel.

I'm unsure if perished fuel pump seal would cause this, or fuel filter blocked to f*ck meaning when left with just lift pump priming up for a minute it runs and then when running can't suck enough through to run for long?

It was run on veg before I bought it but sat up for a year half really getting confused now as to whats causing it any ideas would be awesome!