Engine knock and lack of pwer

[wayne shaw]

hi, please can someone help, i have a toyota hilux surf, it runs well for a certain time then the engine looses power and has a very load knock like a diesel knock , it has a new turbo fitted , and also a leak on the fuel filter hand pump was leaking , so a new one of those was fitted.
just wondering if it could be something like loosing fuel pressure. please advise