Problem: low oil pressure light comes on only.

Problem: low oil pressure light comes on only when engine is ideal or when I let off on the accelerator pedal.

History of vehicle problem: Due to deployment I had to let my son drive it. He smashed the front passenger corner of the vehicle and he did not properly take care of it, like changing out the oil when he was suppose to or replace the oil filter when he changed the oil, but he did bleeding the brake fluid.

Repairs that have been done: mechanic friend replace the passenger side CV drive axle, change all the engine gaskets out, power steering pump, main intake and out-take radiator hoses, all spark plugs because one of them was flooded with oil (leaky gaskets). We also found some caked-on-oil on the timing belt cover. We had to replace the oil drain plug due to son stripping the original plug and tried to hammer it out. I have gotten an alignment done too. I also found a tiny one drip leak coming from the oil drain plug. I have driven it around for a few days but have not seen any indication of a real leak since the dip stick always show oil level is full.

Can it be the oil pressure switch, if so where exactly is it? Or could it be cause by is very small drip from oil drain plug which would mean changing the whole oil pan? Or a clogged oil pump screen since we found caked on oil on the timing belt cover?