Location: Ontop of the cylinders of your engine.
What does it do? A spark plug ignites the fuel/air mixture in the engine's cylinders allowing the piston to be forced downward as the gas expands and provides you with power.
Replacement: Plan about 4 hours after your engine cools. It takes about 15 to 20 minutes to replace each plug. Check your owner's manual for this information:
1. How many plugs are there
The "gap" of a spark plug is the distance between the electrode and the grounding wire. The distance varies depending on the type of engine you have, and if the gap is not set properly, the plug will not perform properly.
Go to your auto parts store. Find the correct spark plugs for your car, either by asking an employee or by finding them yourself. You may need to pick up some socket wrenches, spark plug sockets (with the gasket), and extension rods, if required.
Check your manual again for the gap size and see if your new plugs need to be adjusted. Most new spark plugs will not require it, but some engines can have different caps depending on whether they're used in a 6 or 8 cylinder engine.
When you get home, park the car, shut off the engine, and open the hood. Let the engine cool for a few hours. You don't want to touch the spark plugs immediately after parking because they can be the hottest part of the engine and you will be burned.
When you're ready to work on replacing the plugs, gather your tools in a tray.
Check to see if your new plugs fit inside your wrench-socket gasket. If they stick to the rubber gasket, remove the casket with a screw driver and use tape instead. Just like taping screws to a screwdriver, the stocket can be taped to the plugs. Don't tape the threads.
Find the distributor spark plug cables. You might need the help of your owner's manual. There will be the same number of cables as there are cylinders and spark plugs. They are often red or black and will be distributed evenly across the engine.
Remove each cable by pulling the caps by some very intense twisting and pulling. Avoid jerking them.
Use a compressed air can and clean away the debris from around the plug.
Using a spark plug socket, remove the plugs from the engine and replace them with new plugs. Be careful not to over tighten them. Tighten them with your finger and then use your wrench to tighten them another 1/16 of a turn.
Put the distributor cables back where they were. The order you removed them should be the same order you put them back on, or the engine will not work peroperly.
Put your tools back in their tray and start your engine. If done properly, it will work!