I have a 1997 F-150 and this morning the oil pressure guage went to zero, oil temp light came on.. Truck is running smoothly, no knocks or sounds.. Oil level is exactly where it should be, a little low but not much. Unlike other posts, it is NOT fluctuating... there is no movement in the pressure guage. I believe the oil pressure switch went bad all at once... If anybody else has had this happen--any info would be great.. it is a 4.6L V8 too.. The switch on my truck is located underneath and back by the axl gearbox--quite a PAIN to get too--any tricks to get the harness off with one hand would also be appreciated...

 

I hope you mean the front axle gearbox. The oil sendor is just below the oil filter on the oil filter adapter. Not to bad to change and likely the problem. If the engine was not making any noise after this happened then I would suspect the sending unit. Just grab the harness connector with your thumb and finger and press the tab as you pull to remove the harness then unscrew the sendor using pliers or socket. Good luck.

 

My 01 did the same thing. Now my motor is seized. I haven't taken the motor apart but I believe the oil pump finally gave out