Engine/Transmission (1994 - 1998) Plug Missing In Injector Pump?

[Matt42]

I spent part of the morning scoping out the return hose replacement job for my 1996. While looking at the injector pump, I saw a threaded hole that looks like it might have had a plug or fitting in it at one time. The hole is on the side of the pump that faces the engine, near the center of the flat area, about 2 inches from the top. The threads look clean, and there appears to be some sort of small chamber (or something) at the bottom of the hole. There was no loose plug stuck between the pump and engine.



The truck runs fine, gets good mileage, and isn't leaking. Does everyone's 12 valve have this empty threaded hole?



Thx.