[emoore924]

So, when you start the car, does it make a LOT of valve noise when you start it for all 15 seconds? Does it clatter until the oil pressure gauge comes up or does it sound normal when you start it, no funny noises, then suddenly the gauge moves?

I used to have a Ford 5.0 that would do this. It would start, sound normal, and the gauge would read zero for anywhere from 15 seconds to like 2 min. It was the oil pressure sensor. Nothing wrong with the oil pressure.

If it sounds normal, no clatter, I'd say sensor or gauge or wiring or ground...