how to troubleshoot Honda Civic 10th Generation (2016-2021) rough idle when warm

Solution

1. Preparation

• Gather all necessary tools and parts.
• Disconnect the battery to prevent any electrical issues during the repair.
• Ensure the engine is cool before starting work.

2. Clean the Throttle Body

• Remove the intake duct connected to the throttle body using a socket set.
• Use throttle body cleaner and a soft brush to clean the throttle plate and surrounding areas.
• Reassemble the intake duct and reconnect any sensors or hoses.

3. Inspect and Replace Spark Plugs

• Remove the ignition coil cover using a socket set.
• Disconnect the ignition coils and remove them from the spark plug wells.
• Use a spark plug socket to remove and inspect the spark plugs; replace if worn or fouled.
• Install new spark plugs with a torque specification of 13 lb-ft (17.6 Nm).

4. Check and Adjust the Fuel Pressure

• Connect a fuel pressure gauge to the fuel rail.
• Start the engine and observe the fuel pressure; it should be within the specified range (typically 40-50 psi).
• If pressure is low, check the fuel pump and filter for blockages and replace as necessary.

5. Inspect Vacuum Lines

• Visually inspect all vacuum lines for cracks or disconnections.
• Replace any damaged vacuum lines to ensure proper air intake.