Replace Spark Plugs for Better Engine Performance

Cost Savings

Checklist Tasks

• Consult manual for correct plug type and gap specifications.
• Label ignition wires or coils before removal to keep firing order correct.
• Blow compressed air around plug wells to remove debris.
• Remove plugs from a cool engine to prevent thread damage.
• Use torque wrench to tighten plugs to correct spec.
• Inspect old plugs for deposits or wear indicating engine issues.
• Apply dielectric grease inside ignition boots to prevent misfires.
• Thread new plugs by hand to avoid cross-threading.
• Check and set plug gap with a feeler gauge as needed.
• Replace one plug at a time to avoid mixing up wires/coils.
• Reconnect battery after all plugs and coils are secure.
• Start engine and listen for smooth idle; recheck if rough.