What Causes Overly Rich Air-Fuel Mixture in Cars?

[BrandonLee]

Reasons for overly rich air-fuel mixture in cars: 1. Idle speed, engine meeting torque requirements leading to overly rich mixture; 2. Oxygen sensor failure; 3. Inaccurate air intake measurement - check for fuel injector leakage and the working performance of the fuel pressure regulator, as poor performance can also cause an overly rich mixture. The air-fuel mixture in cars refers to the combination of fuel and air, typically gasoline, diesel, etc. mixed with air. However, with advancements in automotive technology and fuel diversity, it now also includes mixtures with various combustible gases such as natural gas, methane, coal gas, as well as ethanol, methanol, and other mixtures.