Gather tools and parts: correct spark plugs, spark plug socket, ratchet, torque wrench, gap gauge (if needed), dielectric grease (optional), anti-seize (optional), extension, brush/wipes, compressed air (optional), rags
Ensure the engine is cool
Locate the spark plug wires or coil packs
Remove any engine cover or components blocking access
For spark plug wires: grasp the boot, twist lightly, and pull to remove without yanking the wire
For coil packs: remove the coil retaining fasteners, unplug the electrical connector, and pull the coil straight out
Clean the area around each spark plug to prevent debris from entering the cylinder
Remove the old spark plug using the spark plug socket and ratchet (use an extension if needed)
Inspect the old spark plug condition (optional) and verify the correct plug type for your engine
Check and set the new spark plug gap to the manufacturer specification (if the plugs are not pre-gapped)
Apply a small amount of dielectric grease to the inside of boots/connector ends only (if using boots/coils that require it)
Start each new spark plug by hand to avoid cross-threading
Tighten the spark plug to the manufacturer torque specification using a torque wrench
Reinstall the coil packs or wire boots:
Coil packs: seat firmly, reconnect electrical connector, reinstall fasteners
Wire boots: push until fully seated
Repeat for all cylinders, keeping track of wire/coil positions
Reinstall any removed covers or components
Reconnect battery if disconnected
Start the engine and listen for normal operation
Verify there are no misfire symptoms and that the check engine light is not triggered