Engine Help 2.5td

HERES MY PROBLEM

I`VE JUST FITTED A 2.5 TD INTO MY SERIES 2 IT STARTS AND STOPS FINE NOW I`VE SORTTED THE BRAKES OUT
BUT NOW ITS CUTTING OUT ON ME.
OWNCE STARTED AND WARMED UP I PULL OFF IN FIRST AND REV IT TO ABOUT 4500 RPM THEN THE SAME IN SECOUND TO ABOUT 4500 RPM THEN IN THIRD ITS STRUGLES TO GET TO ABOUT 3800 RPM AND THEN IN FOURTH IT STRUGLES TO GET TO ABOUT 3200 RPM THEN CUTS OUT (JUST GUESING THE RPM`S).
STARTS UP OK THEN IT ALL HAPPENS AGAIN SOME TIMES FURTHER DOWN THE GEARS AND REV RANGE.
ALL HELP WELCOME.
THE ONLY THING I CAN THINK I`VE DONE WRONG IS THE FUEL LINES AND IF ANYONE CAN POST A DIAGRAM OF FUEL SYSTEM IT WILL BE A BIG HELP.
THANKS ADAM

sounds like its not getting enough fuel. did you use the old petrol lines? new filters?
the fuel pumps do give problems now and again too.

or possibly the IP needs adjusting.

YES FITTED NEW FILTER

Could be a dirty fuel tank Blow back down the fuel pipes to the tank.

could be **** in the tank that is being sucked up and partially clogging the pick up pipe. then when it stops the stuff drops orf again. start engine, pump sucks up ****, blocks pick up , engine dies, **** drops orf and we start all over again.
the joy is that at lower engine speeds you use less fuel so even though it is partially blocked there is enought getting through to run at low speeds.