What is a common result of an improper spark plug electrode gap?

An improper spark plug electrode gap can lead to an engine misfire, which occurs when the spark plug fails to produce a strong enough spark to ignite the air-fuel mixture in one or more cylinders. When the gap is either too wide or too narrow, the spark may not be able to jump across the electrodes effectively, resulting in incomplete combustion. This misfiring can cause the engine to run unevenly, produce a rough idle, and display a lack of power, as well as lead to increased emissions.

While other issues such as engine overheating, poor fuel efficiency, or excessive vibration may occur due to various factors, they are not directly caused by an improper spark plug gap. Engine overheating is often associated with cooling system issues, poor fuel efficiency can result from multiple factors including fuel delivery and air intake, and excessive vibration might stem from physical imbalances or misalignments in engine components. Thus, the misfire linked specifically to an incorrect spark plug gap stands out as the most direct and common consequence in this context.