how do I fix the P0301 misfire code on my Honda Civic 10th Generation (2016-2021)?

Solution

1. Preparation

• Tools Required: OBD-II scanner, socket set, torque wrench, multimeter, compression tester, fuel pressure gauge.
• Disconnect the battery to prevent electrical shorts.
• Allow the engine to cool before starting work.

2. Inspect Ignition Components

• Ignition Coil Replacement:

  1. Remove the engine cover if applicable.
  2. Unplug the electrical connector from the ignition coil.
  3. Remove the mounting bolts using a socket set.
  4. Pull the ignition coil out of the spark plug well.
  5. Install the new ignition coil by reversing the removal steps, ensuring connections are secure.

• Spark Plug Replacement:

  1. Remove the ignition coil (as described above).
  2. Use a spark plug socket to remove the spark plug from cylinder one.
  3. Inspect the old spark plug for wear or fouling; check the gap with a feeler gauge.
  4. Install a new spark plug with the correct specifications (usually around 0.044 inches gap).
  5. Torque the spark plug to the manufacturer-recommended specification (typically around 13-16 lb-ft).
  6. Reinstall the ignition coil.

3. Fuel Injector Testing

• Fuel Injector Inspection:
  1. Disconnect the electrical connector from the fuel injector.
  2. Use a multimeter to check the resistance of the injector (should be around 12-16 ohms).
  3. If out of specification, replace the fuel injector.
  4. Reconnect everything securely.

4. Compression Testing

• Compression Test:
  1. Remove all spark plugs to facilitate testing.
  2. Install the compression tester into cylinder one.
  3. Crank the engine for several seconds and record the compression reading.
  4. If the reading is below the manufacturer's specification (typically around 180-200 psi), further investigation is needed for internal engine issues.

5. Reassemble and Test

• Reinstall any components removed, ensuring all bolts are torqued to specification.
• Reconnect the battery.