Removal (5.3L)
WARNING: This page is about a different car, the 2003 Oldsmobile Bravada, 2003 GMC Envoy XL, 2003 GMC Envoy, and 2003 Chevrolet TrailBlazer. However, it is still accessible from the selected car via links, so may be relevant.
Remove the spark plug wires. Loosen each spark plug 1 or 2 turns. Brush or air blast away any dirt from around the spark plugs. Remove the spark plugs one at a time. Place each plug in a tray marked with the corresponding cylinder numbers.