A: When it comes to changing spark plugs, besides the new plugs, one needs a socket wrench, with a compatible spark plug socket; a wire-type feeler gauge for checking and adjusting spark plug gaps; and a torque wrench to tighten the new plugs to the specified torque. Socket should be rubber lined so that it protects the porcelain insulator of the spark plug while holding it when being put in place in the hole. This is why you need to have new ones ready before you start, set their gaps and replace them one by one. Check that there are no defects such as cracked porcelain insulators on any of the new plugs; if there are do not use them. Also make sure that side electrode is correctly aligned with center electrode. To avoid confusion when putting back these wires, do only one plug at a time by twisting it half way then pulling off wire and boot attached together. Where available use compressed air or pump blow out dirt and other materials near where spark plug seats. A special ratcheted socket will be used to take out old plugs of all kinds. Finally, assess each old spark before you conclude on how well your engine works overall. Use short piece of rubber hose over end of plug like universal joint helps alignment into hole without cross-threading happening Attach wire leading into this boot tightly around any part on top of its head Repeat this process for remainder of plugs making sure that they are changed singly in order not to mix up cables.