The most important tool is a socket wrench with an extension and a spark plug socket. Spark plug sockets come in two sizes: 5/8 inches and 13/16 inches. Most spark plug sockets have a rubber insert that holds the plug snugly in place. You may also need a universal joint if your spark plugs are difficult to reach.
The engine idles roughly.
You have trouble starting your car in the morning.
Your car’s engine misfires.
Engine surge or hesitation.
High fuel consumption.
Lack of acceleration.
How do you know when spark plugs need to be replaced?
If you’re not keeping track of your mileage, here are some signs your spark plugs or ignition wires are due to be serviced or replaced: