how to fix P0301 misfire in Honda Accord 9th Generation (2013-2017)

Solution

1. Preparation

• Tools Required: OBD-II scanner, socket set, torque wrench, compression tester, noid light, vacuum gauge, safety goggles, gloves.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Inspect and Replace Spark Plug

1. Remove the ignition coil cover if present.
2. Use a socket wrench to remove the spark plug from cylinder 1.
3. Inspect the spark plug for wear or fouling. Replace if necessary.
   • Spark plug gap should be set to specifications (typically 0.043 inches for Honda).
4. Install a new spark plug by hand, then torque to the manufacturer's specification (usually around 13 lb-ft).

3. Check and Replace Ignition Coil

1. Disconnect the electrical connector from the ignition coil on cylinder 1.
2. Remove the ignition coil using a socket wrench.
3. Install a new ignition coil, ensuring it seats properly.
4. Reconnect the electrical connector.

4. Test Fuel Injector

1. Disconnect the fuel injector connector for cylinder 1.
2. Use a noid light to check for pulse. If the light does not blink, further investigate wiring or ECM issues.
3. If the injector is faulty, remove it and replace it with a new one.
4. Reconnect the fuel injector connector.

5. Perform Compression Test

1. Remove the spark plug from cylinder 1.
2. Insert the compression tester into the spark plug hole.
3. Crank the engine for a few seconds and record the reading.
4. Compare the compression reading against the manufacturer's specifications (typically around 180 psi). If low, further engine inspection may be required.

6. Inspect for Vacuum Leaks

1. With the engine running, use a vacuum gauge to check for proper vacuum levels.
2. Spray a small amount of carburetor cleaner around the intake manifold and vacuum hoses. If idle changes, a vacuum leak is present.
3. Replace any damaged hoses or gaskets as necessary.