For anyone that can help. With my 2000 F-150 5.4L 4x4, oming to work this morning, my idiot gauge needle dropped to below the L mark and my oil light came on. I just check the oil this past sunday and it was about a quart low so I topped it off. I change the oil pretty regular but it has been several months since the last change. The motor has about 195K on it. I'm hoping that this is something simple and not expensive. Any clues where to check first?

 

However, after I shut it down and the started it back up, it went off???

 

I would start with getting a mechanical gauge and watch the pressures to see what the actual pressure is. If the pressure stays within range, a common failure point is the oil pressure sending unit. If the oil pressure drops on the gauge, more than likely it is a weak fuel pump.