It's a liar now...
I do believe my gauge is a fibber, ever since the reflash was done.
Since the reflash, I can hook up my 5er(9000 lbs+/-), hammer down up a 15 mile long steep Eastern Sierra grade, pull over at the top with a well heat soaked motor, and it will show 40 lbs of oil pressure at an idle. Before the reflash, oil gauge for the same run would be in the lowend of the normal operating range of the gauge. I find it hard to believe that a Cummins engine has 40 lbs of oil pressure at an idle under this situation. Who has a mechanical gauge on their truck than confirm or deny this?
Unfortunatley, once they do the reflash there is no going back. I would suggest to anyone who has this problem to first try replacing the sender themselves. If it doesn't work, you will just be out a few bucks for the sender, you can then let them reflash it. Once it is reflashed, it's a done deal. I wish I had known this a year ago.
Sam