Pressure drops quick

[panteramatt]

I noticed the pressure in my home would run fine then drop and stay that way I checked the pressure and it was too high. I adjusted the pressure switch and now it kick off at 60 but when running water itll drop down a little then drop fast below 40. Also now my pump needs to run the entire time Im running water and as soon as I turn the wateer off it stops. I checked air pressure in the tank and its at 38psi.

 

[ExtraMilePlumbing]

Could be a bad prv valve

 

[speedbump]

Your tank is set wrong. Did you check the tanks pressure when it was empty and had no system pressure? If not, you only read system pressure. The reason the pressure goes from 40 to zero is because at 40 the tank is empty of water. The 40 lbs of air pressure above the bladder pushes the water out until there is no more to push. At that moment there is no water pressure in the system.
Read the top line on this page: https://www.pumpsandtanks.com/faq/