Navara 2.5 diesel only reaching 2,000 rpm

2007 nissan navara

They have the best manuals:))

a common part over looked when a turbo is bad the drain tube gets plugged and oil cant drain

Your duplicate question did not say it was a diesel.
Usually black smoke on a diesel is dirty injectors or the engine temp not reaching normal range.

IF ENGINE SMOKING WHITE INCORRECT INJECTION TIMING TIMING RETARDED FUEL FULL OF AIR BUBBLES. IF YOU SEE BLACK SMOKE TIMING IS ADVANCED. IF YOU SEE LOT OF HEAVY BLUE SMOKE LOW COMPRESSION ENGINE BURNING OIL.

Dose it run on all cylinders or run rough when idling or jerking when taking off or engine getting hotter than it used to, when going from gear to gear dose it pull as good as before,do you use any oil in 1000 km's or coolant ,dose the exhaust blow black smoke or blue smoke .
IS IT A DIESEL as all these things come in to it plus air filter bunged up ,air leak in intake manifols ,fuel filter or fuel pump needs checking and or replacing ,.
Without seeing it we can only say what it could be.
So let me know how you get on.
Ron

Nothing to fix friend. See, in diesel, when cold, there is an electric plunger on the throttle that speeds the idle a bit till warm up. Connected to that same wire is the cold start/temperature sensor. When cold/cool this sensor will excite the plunger to speed the idle, and put more fuel into the engine making the smoke you see, until warm up is reached and the sensor shuts down. You really don't have a repair needed friend.

The ideal idle rev rate for your vehicle should be approx 800 rpm. If the engine is surging in revs and then dropping off shortly after starting from cold, then it may be that your engine is trying to compensate for the fact that your thermostat has not yet opened. It would help to know if the engine revs settle down after the thermostat opens. Diesels do not have spark plugs, they have glow plugs that preheat the air within the piston chamber so that first starts will occur without a huge drain on the battery, this means that the engine relys on the compression of the diesel and air mixture going into the piston chamber to reach maximum compression and then explode thus causing the power stroke within your engine. But when an engine is cold the engine has trouble sometimes reaching that explosive temperature within the chamber and sometimes not all of the power is released with each stroke of the engine. When the temperature rises and the the thermostat opens the engine can reach the explosive temperature more efficiently and the revs settle down to a more even rate.

Check to see if your air is getting through the turbo alright, sometimes a simple thing like a blocked airfilter can cause symtoms such as what you describe, failing that I would get your Diesel pump checked out, that may have a slight blockage. As an afterthought, have you checked your diesel filter(s) and fuel lines, they may need cleaning out as well. That may cause the rough running until the diesel warms up and flows better through the fuel lines.

Hope that helps.

Check for an airlock in the fuel filter.

Not sure what you mean by "heavy on diesel".   Most diesels, except for late models say 2005 or newer, will have a tiny amount of smoke when cold.  It's hard for a cold motor to combust diesel without a little smoke.  
My money would be on one or both of the other two injectors, dirty, dripping or bad spray pattern.  If you near anything lke a small city, you may be able to find a shop that has the abilty to clean and check them. I use a big marine diesel shop, RPM, in Ft Lauderdale, they can generally get injectors back to new for cheap (maybe $30 each) and have a big expensive high tech machine to test them (they can afford to, they use them for engines on million dollar yachts, among others).  The hyundai injectors might be cheap, the Bosch ones are not.
Injector cleaner in a can that the parts store is happy to sell you, has not worked for anyone I know.   
If you ever lay the car up (e.g. go away on holiday for a month so) put additive in the diesel to keep bacteria from growing in it.  If you can't get it in the auto store, try a marine store.

a stuck EGR valve, dyno the vehicle and fix the EGR, (exhaust gas temp dropped from 650deg due to exhaust gasses constantly being fed back through the engine to 480). Fuel economy back is to normal.