I have a 00 silverado 4x4 4.8 vortec with 200000 k I use 5w40 full syn. and use prem. gas every 3 rd. fill also I change the oil every 5000 k and use injecter cleaner every oil change. I have no cold knock or ping this motor runs as strong today as when it was new. The only problem I have had is a exhuast leak at the manifold and when I start it it has a ping till it warms up. This is now been fixed . But I was told the gaskets on 4.8\5.3\6.0 are paper thin and leak making a ping till it warms up. To check put in gear hold brake and give it a little gas if the ping stays the same it might be just a bad gasket.
