Once i start the truck it reads normal than goes back down it sits right before the N i have good oil level and there is no noises or anything the needle does not move at all even when i rev up any help would be appericated
The "gauge" is just a switch, the sender closes at about 6# of pressure.
So, it could be that you have a bad sender, it's a couple of bucks, but you might need to buy a special socket to change it.
You really should get a real oil pressure gauge and see what the oil pressure really is. Get the cheapest gauge you can find, hook it up temporarily to see what the pressure is, if the pressure is good, get a new sender, and put the cheap oil pressure gauge on the shelf as a test tool.
If you have low oil pressure, then start saving your pennies for an engine rebuild (partial or complete) - sometimes 22 year old trucks just wear out.
Test & Overview in a 96 from 1996 F-150, F-250, F-350, Bronco, F-Super Duty Motorhome Chassis Workshop Manual: The oil pressure gauge is a magnetic movement design consisting of a bobbin/coil assembly, a return to zero magnet and a primary magnet. The shaft and pointer are connected to the primary magnet. The bobbin/coil assembly is pressed into a metal housing which has two holes for dial mounting. The gauge operates through a pressure activated switch. When the engine is started engine oil pressure closes the switch, providing a ground circuit for the gauge coil. Current flow through the gauge coil to ground causes the primary magnet and pointer to rotate, providing an oil pressure reading on the dial face. The oil pressure gauge does not require adjustment, calibration or maintenance. Also, never remove the pointer indicator from its shaft. The oil pressure switch controls the magnetic oil pressure gauge's pointer position. The oil pressure switch closes under normal engine operating conditions (oil pressure above 42 kPa [6 lb/sq in]). The oil pressure switch opens with the engine (6007) off and no oil pressure. Check gauge operation as follows: With the key in RUN and the engine off, disconnect wiring connector at the switch. The gauge should indicate on the LOW graduation or below. Connect the wiring connector to the engine block ground. The gauge should indicate just slightly above mid-scale. If the oil pressure gauge tests within calibration, replace oil pressure switch. If the gauge still tests out of calibration, replace oil pressure gauge.
Source: by Ford
My initial thought is start small and replace the sender and see if that fixes the problem. Bad senders / sensors / etc can really screw you up and make you think you have a worse problem than you really do.
my 93 developed that same problem and i added a mechanical gauge to get a better read on what was going on. The problem persisted and on mine it seemed intermittent, i would shut it off and start it a few minutes later and it was fine again for a few minutes then pressure would drop. It ended up being a clogged oil pump pickup screen in the pan. Cleaned out the pan and screen, replaced the pump and it has been bomber ever since. My truck had around 170K on it at the time and also would not change with rpm btw.