sluggish 4.2 patrol

Blocked Fuel Filter - Diesels need them changed more than petrols?
Standard tires - gearing could be out of wack with bigger hoops?
Any modifications to the engine/car?
Injectors clean - does it blow smoke?
Clutch slipping?
Been serviced recently?
Has it just started eg since service? What does the servicing agent say?

If the vehicle performs ok elswhere then try low range to get the boat out of the water. For a short distance only. After all you paid for all those gears.
Most 4.2 td are very lax in power low down.

Pull the standard fuel filter off and fit a CAV 296 7111 filter assembly. But get the one with the hand primer pump on it and not the conversion one to fit your standard primer. CAV is now owned by Delphi but still the same thing.

Anwers to Trucksters questions.

Fuel Filter was replaced 2000kms ago with a ryco replacement (same time as service)
Still has standard size tyres on it.
Clutch is not slipping.
Doesn't blow black smoke.
Getting my cousins Gu (4.2) to compare against tonight. If it is totally different to his down low then will get my mechanic to look at mine.

Can't even get the revs up to pull up a hill (not steep hills) without riding the clutch big time. (foot to the floor and it just won't rev up & wants to stall)

Clutching at straws here but some time recently nissan made a concession to modern technology and made some part of the fuel delivey (I think) electric and I think computerised (not a full on electric fuel pump like 3.0l) so is it a straight forward mechanical pump coz if it has electric control on it that may be somewhere to look.

Check gauze filter in injector pump . Remove fuel feed line remove spring under this is a fine gauze filter they block up all the time. If no spring under feed pipe no gauze filter is fitted
Steve

Hmmm,
You say this only happens when taking off on an incline (such as a boat ramp), & OK at all other times, right???
Doesn't sound like a filtration issue to me, as I would have thought that this would be more likely to manifest itself at higher revs...

Where's the fuel pick-up in these?? (must say I've never checked)...
Is it towards the rear of the tank?

I'm putting my money on there being something inside the tank that's kinda settling against the pick-up (presumably, there's a gauze strainer in there??) when the vehicle is stopped facing uphill, thereby partially blocking the fuel flow at that point, & then "sloshing around" in there once you get moving, & the problem "goes away" 'till the next time you stop in a similar position...
PITA job, I know, but it could be worth your while removing the tank & emptying / flushing it out, & see what you find...

Regards, Ed. C.