Cac replacement

[Chamberpains]

Which model cummins are we talking about?

I would start by monitoring all the sensors plus the turbo activity. How often does it do the violent boost fluctuations? Can you replicate it? If so that's when you want to be recording the sensor and data output with Insite. Quite possibly one of those jokers are jumping around waving their arms around saying I'm not ok or my wiring is bad. But you often times have to catch them in the act.