Jerry, can you get the codes? Once you can read a code you know exactly where to look. DD and Prevost have 24 hour phones.

You can either read the code as I described above or by running a jumper as I did in my old coach.

As your last description indicated it is a situation found only at idle. The 8V92 is a low oil pressure engine at idle, but there is still a minimum pressure required and now I am leaning toward that just because of how you last described it. I think the oil pressure sensor is located on the forward upper bulkhead right under or near the rear oil pressure gauge.