4JX1 cutting out on idle half warm

[motylewi]

I have an Isuzu Trooper year 2000 with the 4JX1 engine.
It starts quite good, has full power and goes quite good, but when its half warm it goes out on idle. When I push the gas pedal, it runs normal without any Problems, but when I take my foot off the pedal, it just goes off.
When its completely cold or completely warm, it has normal idle, no Problems.
Half warm means when its been driven about 10 minutes or been left warm about one hour standing.
The oil and both filters have been replaced about 3000km ago, I also changed the coolant temperature sensor and cleaned the RPCV.
The o-rings on the Injectors seem to be ok, I have no Diesel in coolant or oil.
Does this Sound like it could be the ORPS sensor?