Oil light comes on when stopped

[Suave]

I have a 92 corolla (5 speed) and started to notice then when it's fully warmed up and I come to a light and press my clutch in (or put it in neutral) the RPMs drop to about 600-700 and the oil light comes one (usually just flickers). As soon as I touch the gas it goes away. From what I've been able to search it may be the oil pressure sensor, but would that also cause the low idle? Any suggestions? thinner oil/some sort of cleaner product/just raising the idle a tiny bit? Let me know what you think, Thanks

[WERKZinc]

I had mostly the same issue i dont know if i got lucky but i changed the oil (and no i wasnt low on oil b4) and disconnected my battery at the same time due to another project and when i reconnected the battery light stopped coming on. Probably was my sensor though problem may come back but its been 2 weeks. Also my idle was doing the same thing but had nothing to do with my oil light. That was a combo of a vacuum leak and cleaning my idle control valve thingy lol can't think of the exact name right now. You may have totally different issues but check out your vacuum lines and its pretty easy to clean the icv (if thats what its called)may help your idle issue if your in need of an oil change i doubt it will help you aswell but who knows wont hurt changing the oil . i did everything at one time and since than everythings been perfect

[90 GP]

Could be the oil sender. Could replace sender or remove sender to take an oil pressure reading to verify.

[Donald]

I think your idle is low. I think it should be 800 rpm, but I am not sure. My book is outside in the garage right now so I can't check it.
If the idle is correct, check your oil level. Check the oil level anyway.
If the idle and oil level are good, you might try using a heavier grade of oil.

I am going to put my money on the idle speed being low.

The "A" series engines tend to drop oil pressure as they age (like most other engines) but it doesn't seem to be a critical issue, as long as it is good at operating speed.
When you hear a rattling noise coming from the bottom end, or the light is still on above about 1000rpm ............ Then you have a problem.