GTO LS Engine Knock on Start Up

[idreamofthe60s]

I looked at an 06 GTO in a lot. When I started it I heard the engine rattle for a second and then quiet down. Is this common on LS engines?

[zbugger]

I know it's common on LS1's. My '00 Z28 has a bit of piston slap when cold.

[John Wright]

My wife's 01 5.3L Tahoe does it too....