03-26-2016, 01:07 PM
If it is just the boost pressure that is falling it is possible that it is a turbo issue. Not sure how Cummins are, but on Power Strokes there is a waste gate that can have issues with the linkage for it sticking. I have an '02 that is tied wide open all the time because they couldn't get linkage to work properly on a turbo change out.