What should be done before installing spark plugs?

Before installing spark plugs, adjusting the electrode gap is a critical step. The correct gap is essential for the spark plug to ignite the air-fuel mixture efficiently and to ensure proper engine performance. If the gap is too wide or too narrow, it can lead to poor ignition, misfires, and increased fuel consumption.

Measuring the reach, checking the heat range, and torquing to specifications are all important aspects of spark plug installation, but they are typically performed after ensuring that the electrode gap is set correctly. The gap should align with the manufacturer's specifications to optimize the spark plug’s performance within the engine. Addressing the gap first lays the foundation for proper installation and functionality.