Causes of engine vibration

[Bajaman]

There is some discussion about this in my thread here

I would like to start a comprehensive list of causes of engine vibrations at low RPM. So I'll start with the most common, please chime in with your personal experience.

Rack dampener pin (turbo OM617)
Compression
Injector spray pattern
Pre-chamber problems (loss of ball)
Delivery valve sticking/ improper seating
Improper valve lash
Injection pump malfunction (wear/misadjustment)
Air in fuel system
Broken engine mount
Engine balance

What am I missing in this list.

[leathermang]

Engine balance due to the vibration dampner on the front crank rotating ( to improper position relative to the crank ) due to broken key or pin...