Why does the engine speed increase after changing spark plugs?

[McCody]

Increased engine speed after changing spark plugs may be due to mismatched heat ratings. It is recommended to use the same model as the original. Spark plugs are crucial components in a gasoline engine's ignition system, which introduce high voltage electricity into the combustion chamber and generate sparks by jumping across the electrode gap, thereby igniting the air-fuel mixture in the cylinder. Main types of spark plugs include: Standard spark plugs, extended insulator spark plugs, electrode spark plugs, seat spark plugs, pole spark plugs, and surface gap spark plugs. Effects of faulty spark plugs: Damaged spark plugs can directly cause ignition system leakage, increased fuel consumption, reduced power output, and other issues. The most significant impact is difficulty in ignition, affecting the vehicle's normal operation. Severe spark plug erosion - including tip scarring, electrode damage/melting, or burn marks - indicates the spark plug is damaged and needs replacement.