Originally Posted by Diesel911

I did not take the time to spell check:

Good job troublshooting.

When you swapped the Injectors and there was no changed as you said that indicated it was not the Injector.

You took the compression test and found a low cylinder.

You put Oil into the cylinder (which normally is not done on Diesel Engines because there is a chance that Oil pooled on the top of the piston could ignite a bit and ruin your compression tester gauge). So I think you have found evidence that it is not the rings/piston/cylinder.
Becaue normally oil in the cylinder would raise the compression if it was an issue with the rings/pistons/cylinder.

All that I can think of that is left is an issue with the not seating well or a head gasket leak.

If you have an Air Compressor (better if it has a water filter to keep water out of the compressed air) you could mod your compression tester adapter so you can apply compressed air into the Cylinder with the valves closed and it is supposed to be at TDC or close to that.

then you listen for leaks in the intake or exhaust maifold to see if it is a valve seating issue.
I am not sure how easy it is to here if air is leaking into the crankcase for a rings/piston/cylinder issue.

If the headgasket is leaking out side you might here the air hissing out.

If there is a head gasket leak into the coolant after you drive the Car sufficently get it good and hot; shut it off and park it for 2 hours or more. Afterwhich squeeze the upprer radiator hose. If that hose feels hard and inflated you have a head gasket leak into the coolant.

You also might be able to see bubbles in the coolant recovery tank or it could have that burnt combustion smell.

If everything is OK in the above tests all that is left is the Fuel Injecion Pump. Perhaps some issue inside the #2 element (if you have an MW Fuel Injection Pump don't loosen the 2 13mm Nuts on each side of the Element).