The screen disc in the injector holder was clogged almost completely.
But the "clogging material" was a bit different from past experience episodes (on other trucks of the same model).
Usually I find some gummy or oily consistency junk built up on the mesh.
This time was different in that there was a layer of "dry, granular particles" almost like sand in appearance that at first glance hid the screen and circlip entirely from sight.
Because I knew there was no way of pulling the disc up and out of its bore without some of that junk falling into the fuel passage below (and consequently migrating into the injectors) I removed the injector holder and turned it upside down over a clean metal dish on my work table.
Quite a lot (maybe half a tea spoon) of stuff fell out. The grains were easily crumbled when prodded with a finger. I figure the stuff was flaking off of surfaces in the regulator/vaporizer and delivery hose and transporting to the screen. While I had the holder off, I removed the injectors and pressure sensor and cleaned out the stripped holder with spray carb cleaner.
This truck came to us from another terminal back in the spring and so I don't know about how much use it got at its former domicile, but here at this location it is pretty much a "stand by" truck because our operators don't care much for Komatsus.
Out of a fleet of nearly 100 trucks we only have 6 Komatsu trucks, the rest of the fleet are 7F & 8F Toyota.
I think that inactivity is allowing the typically gummy heavy ends of fuel to dry out and subsequently shed off the insides of the regulator/vaporizer.
I removed the Nikki regulator and disassembled it.
The inside surfaces had a lot of dried material coating that is usually very much like tar.
I went ahead and dropped the parts into the soak for cleaning and installed a previously rebuilt regulator on the truck.
All is well now, but I still don't understand the ETCA voltage discrepancies (from the manual) that I see.

Yes the mesh inlet screen to he injector holder s a very good possibility also,have had that one myself also,it is the last chance screen to keep garbage out of the system and does get plugged and clogged. As for the injector,unless you can swap in a known good one ,they don't clean up very well usually

Kevin, was there going to be more to that procedure than what you posted?
I can sort of clean the injectors, but as others have stated before, cleaning may or not give good results.
One other thing that occurred to me that I have not looked at yet (only a brief time on this truck before end of shift last night) is maybe the mesh screen in the injector holder casting.
I did observe that the LPG fuel pressure value shown on the Hitachi would fall to around 14 kpa (from around 26 kpa at idle) when the accelerator pedal is pushed down with engine running
I will check that when I return to work Friday.
The voltage values I am getting from the ETCA sensors has me puzzled though,

I have had a faulty/malfunctioning injector on a Nissan with the K21/25 Engine do this check to see if the injector is sticking/malfunctioning