how to diagnose and fix a misfire in my Toyota Camry Seventh Generation (2012-2017)

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the battery to prevent electrical shorts.
• Allow the engine to cool before working on components.

2. Replace Spark Plugs

• Remove the ignition coil(s) by unbolting and disconnecting the electrical connector.
• Use a spark plug socket to extract the old spark plugs.
• Inspect the spark plug gap and replace with new plugs if worn (typically NGK or Denso, gap: 0.043 inches).
• Reinstall new spark plugs and reconnect the ignition coils.

3. Inspect and Replace Ignition Coils

• If ignition coils are found faulty, remove them by unbolting and pulling them off the spark plugs.
• Install new ignition coils (ensure they match OEM specifications).
• Reconnect the electrical connectors securely.

4. Check and Clean Fuel Injectors

• Remove the fuel injectors from the fuel rail (ensure fuel pressure is relieved before removal).
• Clean injectors with a professional cleaning kit or replace with new ones if clogged.
• Reinstall the cleaned or new injectors with new O-rings to prevent leaks.

5. Repair Vacuum Leaks

• Inspect all vacuum hoses for cracks or disconnections.
• Replace any damaged hoses and ensure all connections are tight.
• Use a smoke test to find leaks if necessary.

6. Perform Compression Test

• Remove the spark plugs and connect a compression tester to each cylinder.
• Crank the engine and record the compression readings.
• Compare to manufacturer specifications (typically around 180-200 psi).
• If readings are low, further investigate mechanical issues (e.g., valve seat, gasket leaks).