2012 ISX 12 CM2250 - rough under throttle

[Mikanic]

Grayish smoke.. makes me think of exhaust valves staying open maybe... engine brake actuator bypassing excessive oil pressure in rocker shaft when deactivated? Loose or stuck exhaust brake plunger when cold. I dont know if cummins have a procedure to monitor oil pressure in rockershaft, I know volvo does. You did a top set but maybe it would be good to take apart the engine brake rockers aswell.

Also if turbo is acting up, monitor exhaust gas pressure, is it stable when turbo is stable? Is it acting up before the turbo? I seen bad exhaust gas pressure connector make the value unstable but still valid and the turbo was acting up weird without setting faults for hours of operation before setting a fault.