last winter my 2000 f150 5.4 when started would not register oil pressure on the gauge for up to 3 miles, depending on outside temp. When I pulled over and checked oil, it was full and pressure registered when I started back up. It happened numerous times.
Truck has 82000 miles on it. Any sugestions?

 

Yes change the oil gauge sending unit located at the oil filter adapter, driverside front lower engine.