intermittent oil light

I have a 98, 2.2 L chevy cavalier with 220,000 miles. I have been noticing on a couple rare occasions that the oil pressure light would come on. (oil level full) Once upon starting and once after driving a couple miles. After turning the car off and restarting, the light goes away. Any ideas?

Is the oil light for pressure or for level?

If for pressure, it could be a bad sensor......only way to know would be to remove the sensor and attach a mechanical gage to check pressure....think pressure should be around 40psi....that's what it was in my old 2.2 in my S-10.....or with 220K miles, could be worn engine(oil pump, bearings, etc)....