how to diagnose misfires in my Ford F-150 13th Generation (2015-2020)

Learn how to diagnose and fix engine misfires in Ford F-150 (2015-2020). Step-by-step guide with symptoms, diagnostic steps, and repair instructions.

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Replace Spark Plugs

• Tools Required: Socket set, torque wrench, spark plug socket
• Instructions:
  1. Remove the engine cover if equipped.
  2. Remove the ignition coil(s) from the affected cylinder(s) by unbolting and disconnecting the electrical connector.
  3. Using a spark plug socket, remove the old spark plug(s) and inspect for wear or damage.
  4. Install the new spark plug(s) by hand to avoid cross-threading, then torque to the manufacturer’s specification (usually around 13-15 lb-ft).
  5. Reinstall the ignition coil(s) and reconnect electrical connectors.

3. Inspect and Replace Ignition Coils (if necessary)

• Tools Required: Socket set
• Instructions:
  1. If the ignition coils show signs of wear or malfunction, remove them as detailed in the previous step.
  2. Install new ignition coils by reversing the removal process, ensuring they are seated properly and connected to the electrical harness.

4. Clean or Replace Fuel Injectors (if necessary)

• Tools Required: Fuel injector cleaner kit or replacement injectors
• Instructions:
  1. If injectors are clogged, either clean them using a fuel injector cleaning kit or replace them with new parts.
  2. Follow specific instructions provided with the cleaning kit or replacement injectors for proper installation.

5. Check for Vacuum Leaks

• Tools Required: Smoke machine or carburetor cleaner
• Instructions:
  1. Use a smoke machine to check for vacuum leaks or spray carburetor cleaner around vacuum lines and intake manifold while the engine is running to see if idle changes, indicating a leak.
  2. Repair any damaged vacuum lines or gaskets found during inspection.

6. Perform Compression Test (if necessary)

• Tools Required: Compression tester
• Instructions:
  1. Remove spark plugs and insert the compression tester into the spark plug hole.
  2. Crank the engine for a few seconds and record the pressure reading.
  3. Repeat for each cylinder and compare results. Low compression in any cylinder indicates a potential internal engine issue.