Spark plug replacement requires a spark plug socket and extension that fit 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. The gap can only be checked, and if incorrect, the spark plug must be replaced. When replacing plugs, purchase new ones, check for proper gap, and replace each plug one at a time, inspecting for defects such as cracks in the porcelain insulator. The electrode gaps should be checked using the wire gauge, ensuring the gap is identical to the recommended specification; if not, the spark plug must be replaced. If the side electrode is not aligned with the center electrode, the spark plug should also be replaced. During removal, clear any dirt from the ignition coil area with compressed air, remove the ignition coils, and then use the spark plug socket with a ratchet and extension to take out the spark plugs. Compare each old spark plug with a provided chart to assess the engine's overall running condition. For installation, apply a thin coat of anti-seize compound to the plug threads, avoiding the lower threads, and use a snug-fitting rubber hose over the spark plug to prevent cross-threading. Tighten the plug to the specified torque and repeat the process for the remaining plugs. After replacing all plugs, reinstall the ignition coils and, for certain models, the intake manifold.