how to fix P0302 misfire code on my Ford F-150 12th Generation (2009-2014)

Solution

1. Preparation

• Tools Required: OBD-II scanner, spark plug socket, torque wrench, compression tester, fuel injector cleaning kit
• Disconnect the negative battery terminal to prevent electrical shorts.
• Allow the engine to cool down before starting work.

2. Replace Spark Plug

• Remove the engine cover if necessary (use a socket set).
• Remove the ignition coil from cylinder 2 by unscrewing the retaining bolts.
• Carefully pull out the spark plug using a spark plug socket.
• Inspect the spark plug for fouling or wear. Replace with a new spark plug if necessary (recommend NGK or Motorcraft).
• Torque the new spark plug to 13 lb-ft (18 Nm).
• Reinstall the ignition coil and secure it with bolts.

3. Inspect and Test Ignition Coil

• If the spark plug appears fine, test the ignition coil by swapping it with another cylinder (e.g., cylinder 3).
• Clear the error codes using an OBD-II scanner.
• Start the engine and check for a new misfire code related to the cylinder that now has the swapped ignition coil (e.g., P0303).
• If the misfire follows the ignition coil, replace the faulty coil.

4. Clean or Replace Fuel Injector

• If misfire persists, check the fuel injector for cylinder 2.
• Remove the fuel rail and disconnect the fuel line (ensure to relieve fuel pressure first).
• Remove the injector and inspect for blockage or dirt. Clean it using a fuel injector cleaning kit.
• If cleaning does not resolve the issue, replace the fuel injector with a new one.

5. Perform Compression Test

• If all previous steps do not solve the problem, perform a compression test on cylinder 2.
• If compression is low, investigate further for potential causes such as valve issues or head gasket failure.