Nissan GUIII 3ltr Diesel Loosing Power

I had the same prob. a few years ago sounds like it could be fuel filters .

Could be
Air flow sensor $1000+
Fuel filters
Air filter
Crap in fuel tank around the pickup etc etc

have you done any sort of trouble shooting yet? Been back to the dealer yet?

You may have picked up a bad tank of Diesel since your last fuel filter change. I would start with the filter.

I have had this very problem and fixed it with the filer change.

Looks like fuel probs to me try the filter change bit then go for a blast.
If not sensor probs $$$$$$$.
Thats why I have a 4.2 fuel gussler just keeps going and usin fuel.

If it doesn't seem like the motor is actually losing power but more like lower "throttle" position, I'd be checking the TPS (throttle position sensor).

As far as bad fuel goes, my experience in the 3 litre is that the engine will cough and the engine diagnostic warning light will come on and stay on - and over time there will be a slow but continual loss of power until you cant get the beast over 100.

My 4.2 wont tow a 17 foot van over 100ish. Maybe it thinks its grown up a bit. Park it in front of a shop window so it can see its decals on the side doors.

Sean

Mate,
Please feel free to tell me to mind my own business, but I really think you're doing yourself a dis-service by asking ANY vehicle (with the exception of a F250 or a Chev V8 powered patrol/Cruiser) to tow your van at those sorts of speeds for long distances; even on the flat. Towing in 5th gear is not recommended (even though I do it all the time, but my trailer is only about 1200kg)
Having said that, your problem could be related to poor fuel resulting in a blocked filter as suggested earlier.
When we did our recent Cape York trip a few months ago, we fuelled up at Innaminka. My mate and I both used the same bowser. About 1 hour into our trip north from there, he sufferred a similar problem to what you have described, although we were only doing around 80 klicks at the time. In the end his 3 litre passed out and had to be revived. This was a simple proceedure of running some fuel out of the bottom of the filter.
My 4.2 patrol did not suffer the same problems, but I do not know whether is due to the De-Bug fuel unit I use or the fact that the 4.2 is not high tech (the very reason i bought it and not the 3 litre) and may have been better able to process the bad fuel and keep going.
Good luck.....

My totally un educated guess would be to look at the tps.
does the Nissan have onboard diagnostics that another member could help you with?.....usually a matter of shorting two specific pins on the service computer diagnostic plug/socket and counting the number of times a light on the dash or on the computer flashes. Some computers will store the fault codes after the mil light goes out.....and not all faults necessarily activate the mil light.