Sometimes my oe oil pressure gauge drops to zero and I get a ding with a light. This usually only happens when I’m at a lower idle situation while pulling forward and the idle gets low or reversing into a parking spot and idle gets low (idle is set at 815). It’s only happened a handful of times until one day last week when we had a 75 degree day and then it was dinging every few minutes during slow driving or idling. When I bought this truck, a little over a year ago, original owner told me about this and had a new oil switch in the door but I put a new mopar switch in it anyway. Mechanical oil gauge I have shows 23 psi or so while the gauge in the dash drops to zero. Do y’all think this could be a wire or just nature of the beast. Also, cold start oil pressure seems to come up slowly but I’ve never had a mechanical gauge on any of my other cummins. I’m using 15w40 and it’s not low. 

Sensor for dash gauge going bad maybe? I dont how the 12v's read oil pressure.

The gauge seems accurate all times, except when it drops off.

This was the sample. I’ve had two 98 trucks and the first two samples were from it several years ago, but it also had a wix bhaf with good results so maybe I have something else going on

Did you have valve cover off at that sample interval. That could be why some dirt may be in there.

I don’t think valve covers were off anytime during that run.