12/10/2026
Spark Plugs
The spark plug lights the fuel and air mixture in every cylinder. Worn plugs waste fuel and make the engine run poorly.
Common types
Copper: good conductivity, shortest life, needs more frequent changes
Platinum / double platinum: lasts longer than copper
Iridium: the hardest electrode material, with the longest life
Signs of worn spark plugs
Hard starting
Rough idle or misfiring
Poor acceleration
Higher fuel consumption
Tip: Always use the plug type and heat range the car maker specifies, set the correct gap, and tighten to the correct torque. Replace the plugs as a full set so all cylinders fire evenly.