chances are you afm is stuffed, often cleaning them will fix them for a little while with the problem returning, did the car ever have an oiled k&n filter on it? they are a know cause for killing afms

i would replace the afm first thing as they are relatively cheap for your model

Nissan Patrol ZD30DDTI GU 3.0 00-04 air flow meter maf afm ZD30DI | Engine, Engine Parts & Transmission | Gumtree Australia Belmont Area - Cloverdale | 1064049933