High Oil Pressure and Elevation

[rick3000]

Hi,
I just got back from a leisurely drive up to the ski resort and back in my '99 boxster. I had an interesting problem. I arrived and stopped for about 10 minutes and then while I was waiting in neutral to get back on the road to come back down I had a problem. I revving the engine at around 2000-3000rpm to start going and the car died. So I go to restart it and the engine won't turn over, it took about 6-7 seconds turning the key to get it to turn over and then I drove off. The Oil Gauge is normally around 180 but it was at 200. This was at an elevation of 8500 feet and I live at about 5000 feet. As I got back down the mountain the oil gauge went back to 180.

Any thoughts on what this could be? Could be the altitude?
Any way to fix it?
Also it was 85° out.

Thanks!