My son recently bought an 02 LS V8 (116,000mi.), ran great for 6 weeks, then started experiencing "the symptoms". P0316, we replaced plugs and checked coils. Code stayed away. Next day, P0171 & P0174, so we found AF. We're ready to tackle the pcv tubing with some guidance, so I'd really appreciate your pcv files, Shorod. I'll DM you with my email. Looks like a good father/ son project!