how to fix rough idle issue in Honda Civic 10th Generation (2016-2021)

Solution

1. Preparation

• Gather tools and parts.
• Disconnect the negative battery terminal to prevent electrical shock.
• Allow the engine to cool before starting work.

2. Clean the Throttle Body

• Tools Required: Throttle body cleaner, soft brush, clean cloth.
• Remove the air intake duct connected to the throttle body.
• Spray throttle body cleaner into the throttle body and scrub with a soft brush.
• Wipe any residue with a clean cloth.
• Reinstall the air intake duct securely.

3. Replace Spark Plugs

• Tools Required: Socket set, torque wrench.
• Remove the ignition coils by disconnecting the electrical connectors and unscrewing the mounting bolts.
• Pull out the old spark plugs using a spark plug socket.
• Install new spark plugs, ensuring they are gapped correctly (consult specifications).
• Reinstall the ignition coils, ensuring proper torque (typically 7-9 ft-lbs).

4. Inspect and Clean Fuel Injectors

• Tools Required: Fuel injector cleaner kit, fuel pressure gauge.
• Attach a fuel pressure gauge to the fuel rail to check for proper fuel pressure (consult specifications for your model).
• If pressure is low, clean or replace the fuel injectors using a fuel injector cleaner kit following the manufacturer’s instructions.

5. Check for Vacuum Leaks

• Tools Required: Smoke machine or carburetor cleaner.
• Using a smoke machine, introduce smoke into the intake manifold to identify leaks.
• If using carburetor cleaner, spray around vacuum lines and listen for changes in engine RPM.
• Repair or replace any damaged vacuum hoses found during inspection.