I have 60psi at start cold startup but when the motor warms up yhe oil pressure guage shows like 5 lbs. at idle. and around 20 psi at 2000rpms. I have no knocking or any other symptoms of low oil pressure. Any ideas?

If you havent changed ur oil in a while it will do that. Not likely the gauge seeing that it works on startup. But you can get a mechanical gage and see if its says the same. Or You have a few bearing clearances on the large side and they are about to fail.