My oil pressure light was flickering on and off. I immediately thought " uh oh, my oil pump is getting weak. So I took it into BMW for repair. As it turns out when I last had the car detail they pressure washed the engine. When this was done, some water got into the oil senor cover. BMW took a Q-tp and contact cleaner, removed the water and NO MORE PROBLEM! SO if anyone else has this problem, it can't hurt to check this out.

just info for another cause for oil light flicker at idle. check hollow oil feed bolts on cam oiler tube. mine was loose allowing oil to pump out instead of flowing through the oiler tube.