Losing oil pressure
This is on my daily driver 2003 Pathfinder. I drove around the block for 1/2 an hour before the oil light flickers and comes on, turn engine off immediately sit for 5 seconds and start engine pressure back up to 40psi drive another 1/2 hour samething. I've installed a master pressure gauge and on cold idle it has 55psi and slowly drops to about 30psi as temp rises i know all engines do, but the needle bounces 1-3psi in doing this. It will sit there steady for while and then slowly drops to zero. When it gets down to around 10-20psi the needle flucuates 5-10 psi. As i bring the rpm's up pressure comes up as it should but not so much when it warms up. Just done a oil/filer change, i'm thinking maybe clogged pick-up or pressure releif valve. Has anyone had this happen or similar or know what would cause this.
thanks