2004 dodge ram 4.7 no oil pressure reading until you turn it off

Hook up a manual oil pressure gage and verify the oil pressure.

Remove the sending unit on the engine and check the oil press with a test gauge, if the oil pressure is good on the test gauge replace the oil press sending unit on the engine. Note the removal and installation of the sending unit requires a special socket, that is available at any auto parts store, you will likely need the deep version of that socket for a Chrysler product.

If the valve lifters are quiet you most likely have oil pressure even with gauge showing "0".Sounds like the oil pressure switch going bad.I would try that first.

Sounds like the oil pressure sending unit needs replaced.

change sending unit first if aint that which is should be....it will need a new oil pump

Sound like your oil pick up screen is some what clog, if you have good oil pressure at 1st start and then oil pressure gone after running, check screen.

This same thing happened to me it was the oil sending unit that needed to be replaced. It's an easy fix but you have to take off the heat shield to get to it.

This is OK. Oil pressure is always higher when the engine is cold.

As an engine accumulates miles the pressure will start to drop due to bearing clearances increasing.

If this just started to happen you may want to replace the oil filter and or oil pressure sending unit.

CHECK YOU OIL

Had the truck the truck to the shop and they said it was the sensor. I had it replaced and it hasn't screwed up since. If you search out this problem on the net, this is a problem with engine and its oil pressure sensor. Apparently, Chrysler is aware of the problem.