check oil light on
Check oil light is on, oil has been checked and proper amount is in system. Why is the light still on?
Could just be the a malfunctioning sensor in the engine. I would recommend taking it to a mechanic just to make sure.
Is there noise like it's not getting enough oil? Could be the oil pump is not putting out the right pressure, could be sludge buildup. Does it run a little hot? Is the correct oil filter in place?