Chevy suburban 2000 5.3 low to no oil pressure at idle

maybe a dumb question, but have you checked the engine oil level (not trying to be rude) . if you have check the type of oil filter you are putting on. But you mention tapping noises....do they increase slightly as engine rpm increases then dissapear. if so, i would wager that the noise you are hearing would be the hydraulic lifters. the reason you hear them is that they are not getting a sufficient amount of oil pressure...your oil pump might be dead or dying...would go that route.

also, ensure that you are using the correct weight of oil in your vehicle (follow manufactures recommendations)

hope this helps.