04-13-2018 05:01 AM
You have not clearly explained the symptoms. Is the engine speed unstable at low rpm (hunting, surging,rolling) or is the rpm stable but the engine is running rough due to missfire or is the engine running smooth but has excessive vibration ?
The 3126 8NM has an adjustable bumper spring in the governor to specifically smooth out unstable engine rpm problems at idle.
04-09-2018 11:07 PM
When the engine shaking, is at neutral?
The engine is electronic can do cylinder cutout by ET or if mechanical remove the valve cover and do cylinder cutout manually at engine RPM that its shaking to try if the problem is a bad injector.