What Causes Excessive Exhaust Emissions?

[StJasper]

Reasons for excessive vehicle exhaust emissions: 1. Abnormal engine operation: The engine may have issues such as cylinder misfire, spark plug oil leakage, or oil mixing. When accelerating, the engine runs unevenly and lacks power. 2. Dirty vehicle three major systems: This situation usually occurs in relatively new vehicles where test results show emissions slightly exceeding standards by a few percent or fractions. This indicates that the vehicle's exhaust treatment system (including the catalytic converter and oxygen sensor) is not significantly faulty. The cause of excessive emissions may be due to contamination in the vehicle's three major systems (intake system, exhaust system, and fuel system). 3. Catalytic converter failure: Catalytic converter failure is the primary cause of excessive vehicle exhaust emissions.