My oil pressure gauge on my 2000 F-150 5.4 L is acting up when it is cold. When I first start the engine the guage will not show oil pressure, then when I rev up the engine it will then show oil pressure. It will keep doing this until the engine is warmed up.
Do I have a bad oil pressure sender or am I actually losing oil pressure?

 

I would start with replacing the oil pressure sending unit and it would be a good time to install a mechanical oil pressure gauge. Just my 2 cents

 

I agree with 87Ford !

 

Yes, the OE sender was crap. On a lot of engines.