What is the resistance threshold above which engine spark plug wires should generally be replaced?

The resistance threshold for engine spark plug wires is an important factor in determining their effectiveness. Generally, spark plug wires should be replaced when their resistance exceeds 30,000 ohms. This threshold is significant because excessively high resistance can impede the flow of electrical current, resulting in weak or inconsistent sparks. Such conditions can lead to poor engine performance, misfires, and difficulty starting.

Maintaining spark plug wire resistance below this level ensures optimal spark delivery to the engine cylinders, allowing for more efficient combustion. While some sources may note different limits for different vehicles or applications, 30,000 ohms is a widely accepted standard in the automotive industry for ensuring good conductivity and engine health.