Watching this thread pdrayton, mine does some nailing also, along with my previously stated boost pressure (I too am stumped and still troubleshooting!) I plan on taking the complete intake manifold and EGR off for a good crud/soot cleaning. Could this contribute in nailing?

I replaced #1 and #2 leaking injectors with Bosch remains (from Phil) and no more leaks but same nailing. Replaced IP injector nozzle o-rings and seals no-change.

Tell us more about the IP adjustment screw.

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