Locate the spark plugs. If you follow those thick, rubbery wires under the hood, you'll find the spark plugs (one at the end of each wire.) If you have a 4-cylinder engine, your four spark plugs will be at the top of the engine in a row in front of you. If you have a V8, you'll have to reach down on both sides of the engine to get them out, four on the left and four on the right. If you have a 6-cylinder engine, they could go either way, but if you follow the wires you'll find the plugs.