I have just noticed that my oil pressure when idleing is 0 or 5ish. I just replaced the oil filter tree and one of the check valve balls is gone, but before the switch I was running 30psi or so at idle, now I barely get that 3k cruising. Car runs fine, no weird noises, no leaks. I would say its the oil sender but it read fine for a day or two after the swap. As soon as I hit the clutch, it falls to 0. Really got me worried as to whether to drive it or not, any ideas?