Car owners are concerned about conditions under the hood but their attention seems to focus only on a few things. They are very concerned about the alternator and distributor, and they know that they have to change the oil every 5000 or more miles.
Your car's engine is an incredibly complex set of systems designed to work together. The core of the system is where combustion happens. Combustion (the ignition and explosion of gasoline vapors) is what's responsible for moving the pistons inside your engine, and creating motive power that's then transferred to the transmission and then to the wheels.
What's Pep Boys Glovebox? It's the electronic equivalent of that pile of oil stained receipts and disorganized mechanics' quotes in your real glovebox.
When you're changing your vehicle's spark plugs, work on one spark plug at a time: Remove it, inspect it, clean it, and - if it's salvageable - gap it. Then replace it before you move on to the next spark plug in cylinder sequence order.