What will happen if the spark plug gap is excessively large?

When the spark plug gap is excessively large, one of the main issues that arises is the potential for increased emissions. A larger gap requires a higher voltage to create a spark, and if the ignition system is unable to produce sufficient voltage, it can lead to incomplete combustion. This incomplete combustion results in unburned hydrocarbons and other pollutants being released into the exhaust, contributing to higher emissions levels.

Additionally, a larger gap can cause misfires or rough running conditions. While this doesn’t ensure a smooth operation of the vehicle, it often leads to performance issues that may adversely affect engine efficiency. If the spark is intermittent or weak, combustion can be inconsistent, which ultimately throws off the air-fuel mixture and combustion process.

In summary, the correct choice indicates that one major consequence of an excessively large spark plug gap is the increase in emissions due to inefficient burning of the air-fuel mixture. This relationship highlights the importance of maintaining the recommended spark plug gap for optimal engine performance and emission control.