how to diagnose a misfire in my Toyota RAV4 Fifth Generation (2019-present)

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a level surface and the engine is cool.

2. Replace Spark Plugs

• Sub-steps:
  1. Disconnect the negative battery terminal.
  2. Remove the engine cover if applicable.
  3. Carefully disconnect spark plug wires or ignition coils.
  4. Use a socket wrench to remove the old spark plugs.
  5. Inspect the old plugs for wear; compare gap size to specifications.
  6. Install new spark plugs, ensuring they are gapped correctly (typically 0.043 inches for RAV4).
  7. Torque spark plugs to the manufacturer’s specifications (usually around 13-16 lb-ft).

3. Inspect and Replace Ignition Coils (if necessary)

• Sub-steps:
  1. If misfire codes indicate specific cylinders, remove the corresponding ignition coils.
  2. Inspect for cracks or corrosion in the ignition coil housing.
  3. Replace any faulty ignition coils with OEM parts.
  4. Reinstall the ignition coils, ensuring a snug fit and secure connections.

4. Test Fuel Injectors

• Sub-steps:
  1. Attach a fuel pressure gauge to the fuel rail.
  2. Start the engine and monitor fuel pressure (should be within 3-5 psi of specifications).
  3. If pressure is low, inspect for clogged fuel filters or failing fuel pumps.
  4. Clean or replace fuel injectors as needed.