Isx15 2350 no oil pressure at start up

[Mark1000rr]

Im having an issue on my start up it happen to me before after waking up in the morning first start up the truck and no oil pressure reading just O and red light blinking i let it idle for a while but still no pressure so i shut engine off and i start it back up again still no pressure untill the 4th start i let it idle for 1 min and there i got oil pressure reading on my gauge back on normal. The sensor was just replace 8k miles ago brand new from cummins i dont know if the sensor was bad or i have an oil pump issue please help me out if anyone have this experience i would really appreciate it..