What Is The Spark Plug Gap?
All spark plugs must have the proper ‘gap’ to operate optimally. The gap is the distance between the center and ground electrodes. It must be set precisely to ensure the spark plug arcs at the correct voltage.
How to Check the Spark Plug Gap
Modern spark plugs are sold pre-gapped. Nonetheless, the gap is always checked before a new set of spark plugs are installed as an incorrect gap will cause engine issues such as loss of power, misfires, and poor gas mileage.
Your owner’s manual will suggest the proper gap for the set of spark plugs that are recommended for use with your vehicle and your mechanic will check it before installing a new set of spark plugs.
You will know if the spark plug gap is set correctly by inspecting them. An incorrectly gapped plug may show burnt or dirty electrodes, along with the familiar signs of worn spark plugs such as an engine that is missing or hesitating, or exhibits a knocking or pinging noise.
You can also check the spark plug gap using a gap gauge or feeler gauge tool. Run either one of these tools through the spark plug’s electrodes to measure the gap. Then, compare this measurement to the recommended gap measurement in your owner’s manual. If the measurements are not equal, the spark plug is not properly gapped.
