my Toyota RAV4 XA50 (2019-2024) feels like it’s misfiring, what could be causing this?

Solution

1. Preparation

• Gather tools and parts required.
• Disconnect the negative battery terminal to prevent electrical shorts.
• Ensure the engine is cool before starting work.

2. Inspect and Replace 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 and ratchet to remove the spark plugs.
  4. Inspect each spark plug for wear or damage; replace if necessary.
  5. Set the gap on new spark plugs to manufacturer's specifications (typically around 0.043 inches).
  6. Install new spark plugs, tightening them to 13 lb-ft (17.6 Nm).
  7. Reconnect the ignition coils.

3. Test and Replace Ignition Coils (if necessary)

• Sub-steps:
  1. Use a multimeter to test the ignition coils for resistance (refer to specifications).
  2. If any coil is out of spec, remove it by disconnecting the electrical connector and unscrewing it.
  3. Install the new ignition coil, ensuring a secure fit.
  4. Reconnect the electrical connector.

4. Fuel Injector Cleaning or Replacement

• Sub-steps:
  1. Remove the fuel rail by disconnecting the fuel lines and unscrewing the mounting bolts.
  2. Carefully pull out the fuel injectors.
  3. Clean the fuel injectors using a specialized cleaner or replace them if they are clogged.
  4. Reinstall the injectors, ensuring proper seating and sealing.
  5. Reattach the fuel rail and reconnect fuel lines.

5. Vacuum and Compression Check (if misfire persists)

• Sub-steps:
  1. Inspect all vacuum hoses for cracks or disconnected lines.
  2. Perform a compression test on each cylinder using a compression gauge to ensure all cylinders are within spec (typically 150-200 psi).
  3. Address any identified issues, such as replacing hoses or repairing cylinder compression.