Here’s the rest of the procedure for changing your spark plugs. CLICK HERE if you missed part one. Assuming you’re still on track, pull the wire off the end of the plug by gripping the wire it as close to the engine as possible. Some wiggling may be necessary. About.com stresses here not to rip the spark plug wire completely out of its boot, as that will force you to have to replace the wires, too. That’s fine if they’re old and frayed, but otherwise it’s a $100-plus mistake.
Getting a grip on screw-ins and caps
Pay attention to the old wire-plug setup. Some attach to the spark plug wires via a screw-in receptacle, while others attach via a metal cap. Your new plugs should match the old configuration.
With that in mind, loosen the plugs with your ratchet and take them out of the engine. If the old plug looks slightly sooty, that’s normal. However, if it’s white or oily, there could be other issues in play that go beyond the bounds of this article – check with a mechanic. Assuming all goes well, there should be a foam rubber gripping surface inside the spark plug socket that helps hold it in the ratchet while you’re gripping the plug. If there is no rubber, try using electrical tape inside the socket grip to fill the space.
Wire it and fire it
With spark plug wire in socket, hold the ratchet extension and push it into the hole where the previous plug came out. Guide the plug into the hole in the engine carefully, and then screw it into place by hand until the ratchet is necessary. Make it tight, but don’t overdo it, as the metal in the fitting can bend. Just snug it up. Finally, put the plug wires on the new plug. If the wires are worn, now’s the time to replace them. Once the wires are on, start the engine. If it still doesn’t start, consult with a professional.