First, let's do a little research. Here's what I suggest you do:

1) Remove the accordion tube between the air cleaner and the turbo. Is there oil on the turbo compressor wheel? Is there oil inside the accordion tube? Are you losing oil?

2) Are you losing anti-freeze? Is there any sign of oil in the coolant?

3) One by one, undo the connector on each injector until it starts to leak, then tighten. For each injector, this should cause idle to become rough until you tighten it back. Does this happen with each cylinder?

4) Smell the fuel. Does it smell like Diesel, or something else? (someone may have added gas to the tank, rather than Diesel)

Forget a borescope inspection. The only way that would work is if you pull the prechambers.