how to diagnose Ford F-150 Fourteenth Generation (2021-present) P0301 misfire code

Solution

1. Preparation

• Tools Required: OBD-II scanner, socket set, multimeter, compression tester, fuel injector cleaner.
• Ensure the vehicle is parked on a level surface and the engine is cool before beginning repairs.

2. Replace Spark Plug

• Sub-steps:
  1. Disconnect the negative battery terminal to prevent electrical shorts.
  2. Remove the engine cover if applicable to access the spark plug.
  3. Remove the ignition coil from cylinder 1 by unscrewing the retaining bolts and disconnecting the electrical connector.
  4. Use a spark plug socket to remove the spark plug from cylinder 1.
  5. Install a new spark plug with a gap set to the manufacturer’s specifications (typically around 0.030-0.035 inches).
  6. Reinstall the ignition coil and reconnect the electrical connector.
• Safety Warning: Always disconnect the battery before working on electrical components.

3. Test and Replace Ignition Coil

• Sub-steps:
  1. Use a multimeter to test the ignition coil for primary and secondary resistance according to the specifications in the service manual.
  2. If the coil is faulty, remove it and replace it with a new ignition coil.
  3. Reconnect the electrical connector and ensure it is secured.

4. Clean or Replace Fuel Injector

• Sub-steps:
  1. Inspect the fuel injector for cylinder 1, disconnect the electrical connector and fuel line.
  2. If clogged, use a fuel injector cleaner to clean it; otherwise, replace it with a new injector.
  3. Reconnect the fuel line and electrical connector securely.

5. Compression Test

• Sub-steps:
  1. Remove the spark plug from cylinder 1 and install the compression tester.
  2. Crank the engine several times to obtain a compression reading.
  3. Compare the reading with manufacturer specifications; if low, there may be internal engine issues requiring further inspection.