how to fix P0303 misfire code on my Ford F-150 13th Generation (2015-2020)

Learn how to diagnose and fix P0303 cylinder 3 misfire in Ford F-150 13th Generation. Step-by-step guide with diagnostic procedures and repair instructions.

Solution

1. Preparation

• Tools Required: OBD-II scanner, socket set, torque wrench, multimeter, compression tester, vacuum gauge, fuel injector tester (if needed), safety glasses, gloves.
• Disconnect the negative battery terminal to ensure safety while working on electrical components.

2. Inspect and Replace Spark Plug

• Remove the spark plug from cylinder 3 using a spark plug socket.
• Inspect the spark plug for wear, fouling, or damage. Replace if necessary.
• Install the new spark plug and torque to manufacturer's specifications (typically around 13-15 lb-ft).

3. Inspect and Replace Ignition Coil

• Remove the ignition coil from cylinder 3 after disconnecting the electrical connector.
• Inspect for cracks or carbon tracking. Replace with a new ignition coil if it shows any signs of damage.
• Reinstall the ignition coil, ensuring it is seated properly and reconnect the electrical connector.

4. Test Fuel Injector

• Disconnect the fuel injector connector for cylinder 3.
• Use a noid light to check for proper signal to the injector. If there's no signal, inspect wiring and connectors.
• If the injector is faulty, replace it. Remove the old injector and install a new one with a proper O-ring lubricated with engine oil.

5. Perform Compression Test

• Remove the spark plug from cylinder 3 and install the compression tester.
• Crank the engine and record the compression reading. Compare with specifications (typically around 120-150 psi).
• If compression is low, investigate potential internal engine issues.

6. Reassemble and Test

• Reconnect all components and ensure all connections are secure.
• Reconnect the negative battery terminal and start the engine.
• Clear the P0303 code using the OBD-II scanner and check for any recurrence.