In march of '03 after returning from a 70 mile trip at 75MPH /100*C (Engine temp.) my engine started nailing. After some testing, I discovered that is is the #1 cylinder only. Its loud and clear between 700RPM and 3500RPM at all loads.

To try to fix this I have done several things:

1: Valve lash adjustment. No change, runs smother and more powerful.
2: Replace injectors with remanufactured models. Again, no change, smother running, more power.
3: Replaced cam woodruf key with 4*offset. Same results as above.
4: Adjusted IP injection timing. Again, same results.

The nailing is still there, just louder and more clear metalic. Does this mean its and internal problem with the IP? Should I bring it to a diesel shop and have them calibrate it on a IP bench, have it rebuilt, or replace it with a new/remanufactured one?

Could it also be a psyical mechanical problem with the engine as well?

I haven't had any problem with it other than the bad sound. I thank you all in advance for the help you have given on this and all my other posts!