here is an odd though
if it is not the sensor
maybe it is the pump
that is giving adequate pressure under idle
but when sped up it cannot sustain any pressure possible because of wear on the blades
and the ecu recognizes that and throws on the light
so even with full oil ,the car is being starved for oil especially at the upper portions
another thoght is maybe your oil filter is plugged and causeing a blockage
just a thought