Welcome to the Nissan Patrol forum. To post a question and to see less adds on the forum then you will have to register
first. We are an easy going friendly forum so join in the conversations and feel free to ask any questions.
Become a forum sponsor for only $20 and see no adds with faster page loading times and many extras benefits.
There's nothing you can tune with a stock ECU that can change fuel mixtures. You'll need an engine management system for that. I believe Nistune are a popular choice for the 4.2 EFI.
A good fuel pressure regulator is a must. A 1 to 1 ratio boost reference will increase the fuel pressure by 1 psi for each psi of boost. This will compensate for the injectors trying to open against the increased manifold pressure.
It's common practice to also raise the base fuel pressure but this will cause rich idle if the ECU can't adjust sufficiently.
It can also make the standard fuel pump work harder.