1983 OM617 300SD...knocking on cylinder #3. I took known good injectors and put them in its place no change. The car acts JUST like this one in the video...when you rev it up to about 1,000 it it smooths right out, no knock or shake.

https://www.youtube.com/watch?v=rAOVL3C0dvg

I did a diesel purge for 1/2 hour and new filters..Still no change.

Is this a prechamber issue? An injection pump not telling that injector what to do correctly? Or is this simply a valve adjustment needed?

It had a valve adjustment about 3,000 miles ago and I heard sometimes you need to do it twice in a short time span.

Ideas?