Fourtrak engine problem

Hi, I know not landrover but I have seen them used in series landrover so maybe someone can help, I have the 2.8 tdi engine and it's running bad, not too bad on tick over but when revved it seems to be starved of fuel or something with hardly any power to the wheels even with foot to the floor it does about 10mph and even small hills are too much. Hopefully someone can help, thanks