Spark plug replacement requires a spark plug socket which fits onto a ratchet wrench. This socket is lined with a rubber grommet to protect the porcelain insulator of the spark plug and to hold the plug while you remove it from the spark plug hole. You will also need a wire-type feeler gauge to check and adjust the spark plug gap and a torque wrench to tighten the new plugs to the specified torque. If you are replacing the plugs, purchase the new plugs, adjust them to the proper gap and replace each plug one at a time. It's essential that you obtain the correct plugs for your specific vehicle. Inspect each of the new plugs for defects. If there are any signs of cracks in the porcelain insulator of a plug, don't use it. If the gap is incorrect, the spark plug must be replaced. These spark plugs have iridium-coated electrodes. Don't attempt to adjust the gap on a used iridium-coated plug. Remove the ignition coils. If compressed air is available, blow any dirt or foreign material away from the spark plug area before proceeding. Remove the spark plugs. Whether you are replacing the plugs at this time or intend to reuse the old plugs, compare each old spark plug to determine the overall running condition of the engine. Prior to installation, it's a good idea to coat the spark plug threads with anti-seize compound. Also, it's often difficult to insert spark plugs into their holes without cross-threading them. To avoid this possibility, fit a length of snug-fitting rubber hose over the end of the spark plug. The flexible hose acts as a universal joint to help align the plug with the plug hole. Should the plug begin to cross-thread, the hose will slip on the spark plug, preventing thread damage. Tighten the plug. Install the ignition coil, if necessary. Follow the above procedure for the remaining spark plugs, replacing them one at a time to prevent mixing up the ignition coils.