Spark Plug: Operation
Remove the spark plugs and examine them for burned electrodes and fouled, cracked or broken porcelain insulators. Keep plugs arranged in the order in which they were removed from the engine. An isolated plug displaying an abnormal condition indicates that a problem exists in the corresponding cylinder.
Spark plugs that have low mileage may be cleaned and reused if not otherwise defective. Adjust the gap between the electrodes (Fig 1 ) to the dimensions specified in the chart.
Always tighten spark plugs to the specified torque. Over tightening can cause distortion resulting in a change in the spark plug gap. Tighten spark plugs to 27 N.m (20 ft. lbs.) torque.