How do you change the spark plugs on a 2003 Chevy Trailblazer?

Answer 1

First Remove the black plastic box that says 4200 vortec, there are 2 bolts holding it down. Then loosten the air intake tube on the throttle body. Now move the black plastic box that says 4200 vortec, to the side, there are 6 coils visible, you must loosten the screws to lift the coilpacs. Remove spark plugs using a 5 inch socket extension, and a 3/8ths plug socket. When you re-install the coilpacs, first remove the rubber boot that connects to the plug, fit it down onto the plug, then put the coilpac on top, and tighten down the screw. Repeat this process for all remaining plugs.