What are the causes of excessive carbon monoxide in exhaust emissions?

[StDiana]

There are many reasons for excessive carbon monoxide in exhaust emissions, which are detailed below: 1. Fuel injector leakage: If the fuel injector does not close tightly, gasoline will slowly seep out under pressure, leading to excessive fuel supply. Common causes include injector aging, carbon buildup, or impurities in the gasoline affecting the injector's closure. 2. Spark plug aging: Aging spark plugs can result in reduced ignition energy, potentially failing to ignite the air-fuel mixture, thereby increasing the cylinder misfire rate. Misfire occurs when the spark plug fails to successfully ignite the mixture during the power stroke, causing the unburned mixture to be directly expelled, leading to failed emissions. 3. Oxygen sensor malfunction: The oxygen sensor detects the oxygen content in the exhaust, and the ECU adjusts the air-fuel mixture concentration based on the sensor's signal. If the oxygen sensor malfunctions, it can cause the mixture to become too rich or too lean, affecting the exhaust emissions.