Nick -- Hi & welkom hier / welcome
The ECU that the 3,0 Patrol [until end 2002 ] came with was set for Europe and the SA condtions messe3s with those things brains .. they then OVER fuel, burning a hole [or more]
Take the VIN number to a bigger NISSAN Dealer .. have thenm check if your car qualifies fior an ECU compter replacement [be tough .. they will try to bullshit you of "not knowng about it " and some such shirbet.
O K .. IF not due .. they MUST reset the ECU to correct settings for SA .
By now your pistons are damaged on top. The rings are warn and you have lots of diesel in your sump..
Consider replacing the PISTONS, and RIINGS [you CAN do that without pulling the engine] Buy your parts from ALERT ENGINE Spares [100,000 Km Guarantee]
THEN you CHIP that 3,0, do a complete freeflow & branches .. and you wil run with the 4,8's but only use 10 KPL / diesel ..
Speak to REENEN Kritzinger about the techno stuff
ALSO very NB - that VNT Turbu by now needs a "Kit overall" .. I only know Jan Visser at Turbo Works .. [Centurion / Pretoria East] he even might have an exchange unit in stock for you 012 653 2295
Oh -- the INJECTORS must be callibrated as well .. use a reputable BOSCH agency near you.
Don't bring God down to your level of faith ... bring your faith up to His level!