My oil pressure gauge from the cluster goes all the way to "L" marking and then goes back to the center. This occurs while I'm driving. The needle stays on the "L" marking for a couple of seconds, then it shoots right back to normal.
Sorry to hijack your thread, but mine stays in the middle regardless of my oil until I turn the car off. When the car is in diagnostic mode (trick using the odometer) , my oil pressure is at 0. I'm guessing I have a bad sending unit?