Low oil pressure reading - intermittent warning and confusion

[wrbonn]

The warning and engine light came on when starting my 2016 Cayenne indicating my oil was low. Did this several times. I checked the digital oil level display and analog oil gauges for level and pressure and all looked ok. The the engine light and warning went away. Called and brought the car to the Porsche service center. They said they checked it out and drove the car and could not get the warning to come on that day and said it needed to be on for them to trace anything. Picked up car. Three weeks later, hardly driven but now warning comes on and this time says  oil pressure low. Now when warning comes on when starting see oil pressure gauge takes a few seconds to come up then goes back down to 0 again. Call service center and have it towed to them. Now they say there is a noise in the engine and they are taking the engine apart!!!! Could this just have been an oil pump issue? Why couldn't they trace the problem with their diagnostic equipment the first time? Thank you.