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

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Safety gear: gloves and safety glasses.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Inspect and Replace Spark Plug

• Remove Engine Cover (if applicable):
  • Use a socket set to remove bolts securing the engine cover.
• Access Spark Plug:
  • Disconnect the ignition coil connector on cylinder 2.
  • Remove the ignition coil using a socket wrench.
• Remove Spark Plug:
  • Use a spark plug socket to carefully remove the spark plug from cylinder 2.
• Inspect and Replace:
  • Check the spark plug for wear; replace if necessary. Use a new spark plug with the correct gap (typically 0.054 inches for F-150).
• Reinstall Components:
  • Reinstall the ignition coil and reconnect the electrical connector.

3. Test Fuel Injector

• Remove Fuel Injector Connector:
  • Disconnect the electrical connector from the fuel injector on cylinder 2.
• Check for Injector Function:
  • Use a multimeter to check resistance (should be within manufacturer specs).
• Perform a Fuel Injector Cleaning (if necessary):
  • If the injector is clogged, remove it and clean it with a fuel injector cleaning kit or replace it with a new one.
• Reinstall Injector:
  • Reconnect the injector and its electrical connector.

4. Compression Test

• Remove Spark Plug:
  • Ensure spark plug is removed to allow for accurate testing.
• Connect Compression Tester:
  • Screw in a compression tester into the spark plug hole of cylinder 2.
• Crank Engine:
  • Crank the engine for several seconds and record the pressure reading.
• Compare Readings:
  • Compare the reading to the specifications (typically around 120-150 psi). Low readings may indicate internal engine issues.

5. Check for Vacuum Leaks

• Visual Inspection:
  • Inspect all vacuum hoses connected to the intake manifold for cracks or disconnections.
• Spray Test:
  • With the engine running, spray carburetor cleaner around potential leak points and listen for RPM changes indicating a leak.