I have the exact same problem....I just wasted 150 when my mechanic incorrectly thought it was the oil level sensor, moron!....he then changed the oil pressure sensor for free (an $11 part) which just verified that that sensor was fine. His final thought was it was the oil pump, a $600 estimate. Anyways, no more wasting my time with that general mechanic.
My red light flickering (at idle) started the day of my last oil change, about 2500 miles ago. I'm thinking I'm going to take it to the dealer now. Cars got 115K.....so far it's been pretty good.
Did anyone successfully solve their problem? Thanks.