The TD42 and naturally aspirated 4.2 diesel fitted to the Patrols up until 2006?? have a "Fuel Pump Inlet Filter" that is not common knowledge to many owners.
Have experienced problems over the years with the addition of contaminated fuel in the outback.
The problem can usually be controlled by the addition of eg: "Fuel Set" to control the fungal growth in diesel.
These fungal microbes can and do pass through your primary fuel filter element and get hung up in the "Fuel Inlet Filter."
The result is a loss of power and intermittent misfires.
The fix solution is quite simple if you have the necessary tools while you are out on the road.
17mm socket
250mm extension
Rachet or strong back handle
Length of thin wire bent to form a set of inside calipers.
1: Carefully remove 17mm inlet bolt, remove top and bottom gaskets.
2: Swing inlet pipe out of the way.
3: With the wire calipers remove the spring sitting on top of filter.
4: Again with calipers carefully remove filter.
5: Clean in petrol then refit using the calipers ensuring the brass ring is uppermost.
6: Refit spring.
7: Refit inlet bolt ensuring top and bottom gaskets are in place.
8: Ready to start engine.
Added to this it would be advisable to carry a spare filter and gaskets. If the filter blocks it can be cleaned and used again, however an onhand spare saves time and you can be under full power again within 1/2 hour or less.
Caution: Be sure to clean around inlet before dismantling so no dust and dirt enters inlet.
The added photos may help you with interpretation of my discription.
GU Nissan fuel inlet filter
Postition of inlet pipe
Dismantled components
View of inlet
View of clean & blocked filter.