Hey guys. I just changed the oil in my truck Wednesday with Mobil one 5 20 synthetic. Now when I come to a stop and the truck idles my oil pressure gauge drops to zero. But when I go to take off its back up where it has always been in the past. Thinking maybe the sensor is going bad?

 

Our 99 f250 does that with 10w30 when it's low. I'd double check the level

 

I would get a mechanical gauge and make damn sure the oil pressure is good at idle.

 

Sometimes it will have no issues and other times it will. Been driving it for a few days now and it does not make any weird noises different than it already does.

 

Update - It was the sensor. I changed it today and the electrical plug was full of oil. I cleaned it with brake clean before hooking it to the new switch. It had been leaking oil into the connection for some time now

 

Keep in mind that sensor and the dash gauge do NOT really measure pressure----they're simply indications you have or don't have somewhere around 7-15 PSI oil pressure.

If it measured real-time pressure you'd see it rise and fall when idling and as the RPM's changed too.