OIL PRESSURE DROP

As oil heats up it thins out. What weight oil are you using? How long since last oil and filter change? Could try a little heavier oil or try some Lucas oil treatment.

Are you actually using a gauge you installed or the indicator on the dash? The dash unit is only an indicator and the sender is the culprit. Ford had lots of issues with crappy oil pressure senders. Lots! The main reason for a loss of pressure like that is worn out bearings or incorrect viscosity of oil. An oil pressure relief valve would cause the concern all of the time. Install a manual gauge (if only temporarily) and se what the oil pressure is actually doing. Check the dipstick or owner's manual for the proper viscosity of oil. If the vehicle hasn't seen any severe duty and had oil changes at least every 5000 miles, there shouldn't be any low-end concerns. You didn't mention engine noises or leaks. I'll bet that it's the stupid pressure sender.

thanks for your help had manual guage installed same pressure readings. had new oil sending unit installed still same readings.no problems driving no pings or knocks runs good just worried about drop in pressure .just wanted to see if it could be something else. will keep driving until it will not go anymore.

Does it still run?