I Thanks for all of the info. Are both knock sensors the same? I seen a dual wire and a single wire when looking up parts. I seen one of the post talking about using RTV on the knock sensors. Is that to put on the threads or put around know sensor to seal it after it is installed? I'm planning on replacing them this weekend. I also noticed that there are a few different intake manifold gaskets and kits. Any tips on a good one or one to avoid? 2006 with 5.3

 

My truck is a 2006 with 5.3L

 

I would use all GM parts. Harness and sensors and intake gasket kit. All I ever used. Nothing on sensor threads. Torque sensors 15 lb ft. No more No less. Use rtv on the rubber plugs to seal out water. Intake tighten the bolts a first pass in sequence to 5 N·m (44 lb in). Tighten the bolts a final pass in sequence to 10 N·m (89 lb in). Start in the middle work your way to front to back crisscross left to right.