How to Replace the Spark Plugs on a 2002 Nissan Altima 3.5 – If your 2002 Nissan Altima needs new spark plugs, you can perform the change yourself in under an hour. Regularly scheduled spark plug changes will help your engine last much longer. Spark plugs are critical to the proper firing of the engine cylinders and if one of them is dirty or too old, your engine could wear out more quickly that you had planned on.
Tools Used: Tools, 10 mm socket, 16 mm spark plug socket, Socket wrench, Spark plugs
Replace Spark Plugs
Remove the engine cover. This is a large, plastic cover that protects the engine components from dust and debris. There are a few plastic locking nuts that hold the cover in place. Turn them counterclockwise and remove the cover.
Remove the ignition coils one at a time. The ignition coils are located on top of each spark plug. Unplug the wiring harness from the back of the ignition coil and then un-bolt the ignition coil from the spark plug with a 10 mm socket.