my Honda Civic 10th Generation (2016-2021) has a check engine light and runs rough

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the negative battery terminal for safety.
• Allow the engine to cool down before proceeding.

2. Inspect and Replace Spark Plugs

• Remove the ignition coil(s) by unscrewing them from their respective positions.
• Extract the spark plug using a spark plug socket and ratchet.
• Inspect the spark plug for damage or carbon buildup.
• Replace with new spark plugs if necessary, ensuring the gap is set according to manufacturer specifications (typically around 0.044 inches).
• Reinstall the ignition coil and reconnect the electrical connector.

3. Check and Replace Ignition Coils

• If the spark plugs are in good condition, test the ignition coils with a multimeter for proper resistance (typically between 0.5 to 1.5 ohms).
• If any coils are out of specification, replace them with new units.
• Ensure proper seating and reconnect the electrical connectors.

4. Clean or Replace Fuel Injectors

• If misfires persist, remove the fuel injectors from the fuel rail.
• Clean injectors using a fuel injector cleaning kit or replace them if cleaning does not resolve issues.
• Reinstall injectors, ensuring O-rings are lubricated and seated properly.

5. Inspect Air Intake and Vacuum Lines

• Check the air filter for blockages and replace if necessary.
• Inspect the intake manifold and vacuum hoses for leaks, replacing any damaged components.
• Reinstall the air intake assembly securely.

6. Verify Fuel Pressure

• Connect a fuel pressure gauge to the fuel rail.
• Start the engine and check that the pressure is within the manufacturer’s specified range (typically around 40-50 psi).
• Replace the fuel pump if pressure is inadequate.