What are the symptoms of a faulty exhaust valve in a vehicle?

[SimonLynn]

A damaged exhaust valve can cause engine shaking or even stalling during idle. Relevant information about the exhaust valve is as follows: 1. Symptoms of damage: When the exhaust valve is faulty, it cannot control the amount of exhaust gas recirculation. Excessive exhaust gas participating in recirculation will affect the mixture concentration, leading to difficulties in starting, engine shaking, unstable idle, weak acceleration, and other phenomena that impact engine performance. 2. Function: The exhaust valve serves as an oil-gas separator. When functioning properly, it only draws in exhaust gas, not oil. If the exhaust valve is damaged, it loses its oil-gas separation capability, potentially sucking in oil along with the gas, allowing oil to enter the combustion chamber, resulting in oil burning and blue smoke emissions.