Im having the low oil psi. Its showing the po521 code. When I start it up it shows 40psi whether its cold or warm. Then within mins it falls to zero. I replaced the sensor and cleared the code. I didn't even half to drive it before it started doing the same thing on the startup. I have a snap on scan tool and when I check the oil pressure on it when it drops it shows 2PSI. When I shut it down it still shows 2PSI. I need to get this handled asap. I just bought it from a dealer a few hrs away from where I live and hes willing to work with me on it. I got a good deal on the number side of it. Engine sounds as it should not even the slightest tick. Its a 08 with 125k on it any help would be greatly appreciated.