Spark plug replacement requires a spark plug socket and extension that fits onto a ratchet, with the socket lined with a rubber grommet to protect the porcelain insulator and hold the plug during removal. A wire-type feeler gauge is needed to check and adjust the spark plug gap, along with a torque wrench to tighten the new plugs to the specified torque. When replacing plugs, purchase new ones, adjust them to the proper gap, and replace each plug one at a time, inspecting for defects such as cracks in the porcelain insulator. Check the electrode gaps by inserting the wire gauge of the proper thickness between the electrodes; if the gap is incorrect, it is recommended to replace the spark plug rather than adjust it. If the side electrode is not aligned with the center electrode, use the notched adjuster to align them, bending only the base of the ground electrode if adjustment is necessary. For removal, take out the upper intake manifold for access to the rear bank spark plugs and remove the ignition coils. Use a spark plug socket with a ratchet and extension to remove the spark plugs, comparing each old spark plug with a chart to determine the engine's overall running condition. Before installation, apply a coat of anti-seize compound to the plug threads, avoiding the lower threads. To prevent cross-threading, fit a snug-fitting rubber hose over the end of the spark plug, which helps align the plug with the hole and prevents thread damage if cross-threading occurs. Tighten the plug to the specified torque and follow the same procedure for the remaining plugs. After replacing all plugs, install the ignition coils and replace the upper intake manifold.