How to improve the idle speed of the ninth generation Civic

1. Clean the throttle valve: the throttle valve is the door that controls the air to enter the engine. It accumulates too much oil and carbon, which will affect the air flow and thus the idle speed.

2. Replace the air filter: The air filter is an important part to prevent dust and impurities from entering the engine. If the air filter is too dirty or damaged, it will affect the airflow and thus affect the idle speed.

3. Replace the spark plug: The spark plug is an important part of the ignition system. The aging or damage of spark plug will affect the ignition effect, thus affecting the idle speed.

4. Adjust air-fuel ratio: Air-fuel ratio refers to the mixing ratio of air and fuel. If the air-fuel ratio deviates from the standard value, it will affect the idle speed.