My 2004 isuzu KB DC LX AUTO Diesel starts and idles 100% but it doesnt have power and it doesnt rev, wht might be the problem?

Question edited for clarity and add maker.
Question moved to maker category.

So the pump wasn't new? Perhaps it was broken?

Air locks in the system?

Help in the link

https://www.google.com/search?q=Isuzu+kb+250+4ja1+stalls+while+idling

..

welcome to a USA forum
the country with ZERO
isuzu 300tdi ITS A KB truck , you lift off KB AGAIN.
WE DONT HAVE KB IN USA
NO BOOKS ON DIESEL PUMP TIMING OF ANY KB.

KB (no year)
Welcome to the USA Fixya.com forum
we don't have KB here. sorry.
History.(1 line, all bad)
2005 - Isuzu dealers in the United States have , the Ascender SUV,
and guess what?, it's a rebadged GM car here, no more cars here, or Isuzu I-series same.

KB are in Africa, Australia and in EUROPE not here in USA. so no books here to cover it.
nor is it covered here, at our great ,Mitchells online.

The KB300 is a 2.999 liter diesel, some are TDI. (most?)
and is called the 4JJ1-TC. (t= turbo)
That is direct injected, (means check turbo , and scan it first) after checking fuses.
The Check engine light on, same deal.
Check filters. for fuel and air.
2004 the D-max , family , introduced the DDI-ITeq common rail diesel engine.

So next time post your country.
And all symptoms.
power loss?
smoke?
Noises?
warning lamps.
does turbo seem dead, only you can hear it?
etc.


our closest car matching yours.
is Chevy Colorado 2004_+
and Isuzu I-series.
both with GM drive lines. all petrol !

you year stated !!!, no country (Africa or Australia?) must i guess?
we dont have KBs here, (USA) nor books or parts for them.
zero.
gas (petrol) or Diesel

here read this page, see how confusing, KB are world wide
https://en.wikipedia.org/wiki/Isuzu_D-Max

we cant guess any of this, see that?
see why?
if diesel? scan it?
check injection pump pressure. is it direct injector or common rail.
matters. that.

no year?\
no country.
no joy.
no engine, or is 300 means 3liter?
we dont have KBs in USA> this is a usa forum. so...
so the operators guide says.
CEL on get service.
or if handly DIY guy, SCAN IT yet? that is what the lamp means.
SCAN me now. on all cars 1988 to now, in usa,
and 2001 and newer on other countries. varies by country....
as does EFI systems used,.... big time.

why double post
all added year.
but what country
and what engine exactly using real isuzu name for your engine.

what engine is there. some 2.5L but what, gas or diesel?
exactly real engine name... is best.
this usa forum we dont have KB here. ZERO !
and isuzu died here from 2004 to 2008, 1 by 1, ended.
but zero KB here, zero books, and your engines.
you should post to your unstated countries forum on Isuzu.

only 1 clue here.
cutting out.

The engine misfires>? (shakes , but with lost POWER)
or
The engine totally stalls, (zero power)
can the fast right foot action , change the end results.

???
i cant drive it, so you must tell us.
the good, the bad and the ugly.
that means what the engine does right, hot or cold , all driving.modes.