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

Solution

1. Preparation

• Required Tools: OBD-II scanner, socket set, torque wrench, multimeter, fuel pressure gauge, compression gauge.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Replace Spark Plugs

1. Remove the engine cover (if applicable) by unscrewing or unclipping it.
2. Using a spark plug socket, carefully remove the spark plugs.
3. Inspect the spark plugs for wear; replace all four (or more) if needed.
4. Gap new spark plugs to manufacturer specifications (usually around 0.044 inches for Honda).
5. Install new spark plugs and torque to the specified value (typically around 13 lb-ft).

3. Inspect and Replace Ignition Coils

1. Disconnect the wiring harness from the ignition coils.
2. Remove the ignition coils using a socket set.
3. Test each coil's resistance with a multimeter; replace any faulty coils.
4. Install new or tested ignition coils, ensuring they are seated properly and reconnect the wiring harness.

4. Clean or Replace Fuel Injectors

1. Disconnect the fuel pump relay and start the engine to relieve fuel pressure.
2. Remove the fuel rail and injectors carefully.
3. Clean injectors using a professional cleaning kit or replace them if clogged.
4. Reinstall the fuel rail and ensure all connections are secure.

5. Check for Vacuum Leaks

1. Inspect all vacuum lines and intake manifold gaskets visually.
2. Use a smoke machine or spray carburetor cleaner around suspected areas while the engine is running; listen for changes in idle.
3. Replace any damaged vacuum hoses or gaskets as needed.