Moron's answer is: Nailing is an acute affliction of poor "pop" pressure, dirty, or mal-aligned pintal, or carboned up nozzle, or both.

Nailing is identified by hearing 4, 5, and possibly 6 carpenters pounding 10 penny nails into an oak plank, in harmony!

CURE: Diesel purge, or injector rebuild, or add Redline, or Power Services to diesel. Also, B-20 or B-100, and that will cure anything ailing your diesel...BB