Re: Oil light comes on and off
In GM cars, the most common failure is the oil pressure sender even has TSBs on the subject. I had them fail so often I always kept a spare around.
If I saw the light coming on I'd probably check with a mecanical gauge first to see what is really going on and would change the oil, if had not been done for a while (I used to change oil when I'd see the pressure drop 2 psi. Usually worked out to around 2,000-3,000 miles).
Are you running 0W-40 ?
ps long time ago when working at GM was told that at idle you do not need any pressure, just flow. Still use 10 psi per 1,000 rpm as a rule of thumb.