Outer Limits 4x4 Board

Hi everyone. have a 2002 nissan patrol (zd30 3L DDI) that is stalling out at 2000-3000revs and then will not start for 5 minutes or so. when it has been hot, cold.
Have changed the oil, fuel filter thinking it may be those. the mechanic i have been to has checked what the ECU is reading and shows no faults and is stumped.

Does anyone no what is the problem I am having as Its driving me nuts.

dose it have an alarm imobiliser ?

Rail pressure okay?

Dirty fuel at some point?

Injection system clean past the fuel filter?

Fuel pressure regulator clean? This would be the thing that I would be looking at - a piece of debris clogging open the orifice or the mechanism otherwise malfunctioning. Check line pressure versus return pressure.

OBD Compliant? Any readout from that?

It may well be worth a trip to Nissan for a "oncer" service on their diagnostic machine.