08 6.7L with G56, DRD tuned.
Cross-country trip SOON.
It suddenly developed bad vibration.
It's worst at idle while sitting still in neutral but there through all rpm ranges.
There is no correlation between motion and speed.
It seems worse under a light load but goes away under a heavy load and higher boost levels.
I can feel it when the motor turns over before it fires, and the shake at shutdown is highly exaggerated.
The truck seems to run and sound completely normal other than a slight drone in the exhaust note that stated simultaneously.
Things I've checked:
I borrowed a matco diagnostic tool and did an injector kill test.
Everything seemed normal there, but all ran a fuel system check which failed in several steps but gave no explanation on what exactly was being tested or why those steps failed.
I am lost on what else to check; any idea or insight is greatly appreciated.
I have a trip from SC to TX in a few days, and I dont want to grenade anything or be left on the side of the road.