why does my Honda Civic 11th Generation (2022-Present) have a rough idle when cold starting

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the battery to prevent electrical shorts.
• Allow the engine to cool completely before beginning repairs.

2. Inspect and Replace the Spark Plugs

• Sub-steps:
  1. Remove the engine cover (if applicable) using a socket set.
  2. Disconnect the spark plug wires or ignition coils.
  3. Use a spark plug socket to remove the old spark plugs.
  4. Inspect the old plugs for wear or carbon buildup.
  5. Install new spark plugs (use OEM recommended type and gap).
  6. Reconnect the spark plug wires or ignition coils.

3. Test and Replace the Idle Air Control Valve

• Sub-steps:
  1. Locate the idle air control valve (IACV) on the throttle body.
  2. Disconnect the electrical connector and vacuum lines.
  3. Remove the mounting bolts using a socket set.
  4. Inspect the IACV for carbon buildup and functionality.
  5. Replace with a new IACV if defective.
  6. Reinstall the IACV and reconnect all components.

4. Check and Replace the Engine Coolant Temperature Sensor

• Sub-steps:
  1. Locate the engine coolant temperature sensor (ECT) on the engine.
  2. Disconnect the sensor's electrical connector.
  3. Remove the sensor using a wrench; be cautious of any leaking coolant.
  4. Install the new ECT sensor, ensuring it is properly seated.
  5. Reconnect the electrical connector.

5. Inspect the Intake Air System

• Sub-steps:
  1. Visually inspect the air intake hoses for cracks or disconnections.
  2. Remove the air filter and check for dirt or blockages.
  3. Clean or replace the air filter as needed.
  4. Ensure all connections are tight and secure.