UPDATE: Well, the 'check engine' light is back along with engine de-rate and the 'low fuel pressure' error code on the Silverleaf. This time I noticed that while this fault occurred, my electronic odometer got goofy..... it just displays strange characters. I have had this same display intermittently several times with no check engine light but now I wonder if these two issues are somehow related.
If I take it back to Cummins, it will be working fine of course

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