how to fix P0300 misfire code in Honda Accord 10th Generation (2018-2022)

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Disconnect the negative terminal of the battery to prevent electrical shorts.

2. Inspect and Replace Spark Plugs

• Remove the ignition coil by unscrewing the retaining bolts and disconnecting the electrical connector.
• Remove the spark plug using a spark plug socket and ratchet.
• Visually inspect the spark plug for wear, carbon build-up, or damage; replace if necessary.
• Gap the new spark plug according to manufacturer specifications.
• Install the new spark plug and torque to 13 lb-ft (17.6 Nm).
• Reinstall the ignition coil and secure it in place.

3. Check and Replace Ignition Coils (if necessary)

• If any ignition coil is found defective from previous diagnostics, remove it by unscrewing the bolts and disconnecting the wiring harness.
• Install the new ignition coil and secure it with the bolts. Ensure proper connection of the wiring harness.

4. Inspect and Clean Fuel Injectors

• Remove the engine cover if necessary to access fuel injectors.
• Disconnect the fuel injector electrical connectors.
• Use a fuel injector cleaning kit or professional service to clean the fuel injectors thoroughly.
• Reinstall the cleaned or replaced fuel injectors, ensuring they are seated properly.

5. Check Fuel Pressure

• Connect a fuel pressure gauge to the fuel rail Schrader valve.
• Turn the ignition to the "ON" position without starting the engine and check the pressure reading. It should meet manufacturer specifications (typically between 40-50 psi).
• If the pressure is low, replace the fuel pump or check the fuel filter for blockages.

6. Inspect Vacuum Hoses

• Visually inspect all vacuum hoses connected to the intake manifold for any signs of wear or cracks.
• Replace any damaged hoses to ensure proper vacuum levels.