how to diagnose Ford F-150 13th Generation (2015-2020) P0302 misfire code

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the battery to prevent electrical issues while working on ignition components.

Tools Required:

• OBD-II scanner
• Socket set
• Torque wrench
• Compression tester
• Fuel pressure gauge
• Multimeter

2. Replace Spark Plug

• Remove the engine cover if present.
• Disconnect the ignition coil connector for cylinder 2.
• Unbolt and remove the ignition coil.
• Remove the spark plug using a spark plug socket.
• Inspect the old spark plug; replace it if it shows signs of fouling or damage.
• Install the new spark plug and torque it to the manufacturer's specifications (usually around 13-15 lb-ft).
• Reinstall the ignition coil and reconnect the connector.

3. Inspect and Replace Fuel Injector (if necessary)

• If the fuel injector is not functioning, carefully disconnect the fuel line (use caution as fuel may spray).
• Remove the mounting bolts for the fuel rail and gently lift the fuel rail to access the injector.
• Replace the faulty fuel injector with a new one and ensure it seats correctly.
• Reattach the fuel rail and reconnect the fuel line, ensuring there are no leaks.

4. Compression Test

• Remove the spark plug from cylinder 2 again.
• Insert the compression tester into the spark plug hole.
• Crank the engine for several seconds and record the compression reading.
• Compare the reading to the manufacturer's specifications (typically between 120-200 psi); a significant deviation indicates a mechanical issue.

5. Check for Vacuum Leaks

• With the engine running, spray a small amount of carburetor cleaner around the intake manifold and gaskets.
• If the engine speed changes while spraying, there is likely a vacuum leak that needs to be addressed.
• Repair any vacuum leaks found.

6. Verify Fuel Pressure

• Connect the fuel pressure gauge to the fuel rail test port.
• Turn the ignition to the ON position (do not start the engine) and check the pressure; it should match the manufacturer's specifications (usually around 50-60 psi).
• If the pressure is low, check the fuel pump and fuel filter for issues.