Oil light going on and off after 2 hr trip

My sons truck oil light started going on and off after his trip back home. Oil level was good after checking. He let the truck sit for a couple of hours and restarted it. The light came on and after a few seconds went off. He drove it around for a while and it hasn't come back on. Could it be the oil sensor or pcv valve ???

 

What truck ? What engine?
If the oil light goes on that means oil pump is not giving pressure, so don't drive like that. Test oil pressure at idle and 2000 rpms.
If you indeed have low pressure it could be for multiple reasons.
1 bad oil pump
2 clogg oil pickup line
3 one of the seals on oil pickup line is bad and pump sucks air in
4 bad sensor althought very unlikely

 

Don't forget also that if the last oil change used a thinner viscosity oil, or if the oil itself is overdue for an oil change, that can also cause the oil to thin out. Thinner oil reduces oil pressure in the system, and can turn on the light as well. First suggestion, give it an oil change and make sure to use the correct oil and filter.