how to check for misfires in my Toyota RAV4 Fifth Generation (2019-present)

Solution

1. Preparation

• Tools Required: OBD-II scanner, spark plug socket, multimeter, fuel pressure gauge, compression tester, basic hand tools.
• Disconnect the negative battery terminal to ensure safety during diagnostics.

2. Replace Faulty Spark Plugs

• Sub-steps:
  1. Remove the engine cover if necessary.
  2. Disconnect the ignition coils from the spark plugs.
  3. Use a spark plug socket to remove the faulty spark plugs.
  4. Inspect the old spark plugs for wear. Replace with manufacturer’s recommended spark plugs.
  5. Torque the new spark plugs to the manufacturer's specifications (usually around 13-15 lb-ft).
  6. Reconnect the ignition coils.

3. Replace Faulty Ignition Coils

• Sub-steps:
  1. After spark plug replacement, if misfire codes persist, remove the ignition coils.
  2. Inspect the ignition coils for signs of wear or damage.
  3. Replace any faulty ignition coils with new units.
  4. Reinstall the ignition coils and ensure they are properly seated.

4. Address Fuel Issues

• Sub-steps:
  1. If fuel pressure is low, remove the fuel pump assembly from the tank.
  2. Replace the fuel pump if it does not meet specifications (usually 50-60 psi for RAV4).
  3. Check the fuel filter for clogs and replace if necessary.
  4. Reassemble the fuel system and reconnect any electrical connectors.

5. Conduct a Compression Test

• Sub-steps:
  1. Remove the spark plugs to access the cylinders.
  2. Insert a compression tester into the spark plug hole.
  3. Crank the engine for a few seconds and record the compression reading for each cylinder.
  4. Compare readings; if any cylinder is significantly lower than the others, further investigation may be needed (valve issues, gasket failure).