2002 Mercury Sable - Oil light

fresh oil change but oil light still flashes while stopped with foot on brake. Is it a sensor?

It might be. Or it might be low oil pressure. If you have lubrication, you could replace the sensor, they’re usually cheap. If it goes away, your finished. Or you could have your pressure tested with a mechanical gage. I prefer to check with a gage. It gives me assurrance that pressures are adequate. And I also have a gage which makes it more convenient. Be sure the oil level is correct and you have the right filter.