how to diagnose a misfire issue in my Toyota RAV4 Fourth Generation (2013-2018)?

Solution

1. Preparation

• Gather all necessary tools and parts.
• Ensure the vehicle is parked on a flat surface and the engine is cool.
• Disconnect the battery to ensure safety.

2. Replace Spark Plugs

1. Remove the engine cover (if applicable) to access the ignition system.
2. Use a socket wrench to remove the old spark plugs, taking care to avoid debris falling into the cylinders.
3. Inspect the old spark plugs for wear; compare them to manufacturer's specifications.
4. Apply anti-seize compound on the threads of the new spark plugs (if recommended).
5. Install the new spark plugs using a torque wrench; tighten to manufacturer’s specified torque (usually around 13-15 lb-ft for most Toyota models).
6. Reconnect the ignition coils and replace any engine cover.

3. Inspect/Replace Ignition Coils

1. Remove the connectors from the ignition coils.
2. Use a socket to unbolt the ignition coils from the engine.
3. Inspect for cracks or signs of wear. Replace any faulty coils with new ones.
4. Reinstall the ignition coils and reconnect connectors securely.

4. Fuel Injector Service

1. If injectors are suspected, remove the fuel rail (ensure fuel pressure is relieved).
2. Inspect and clean fuel injectors using a specialized injector cleaning kit or replace if necessary.
3. Reinstall the fuel rail and ensure all connections are tight.

5. Compression Test

1. Remove spark plugs to access the cylinder bores.
2. Insert the compression tester into the spark plug hole, ensuring a tight seal.
3. Crank the engine and record the compression readings for each cylinder.
4. Compare readings with manufacturer specifications; replace any cylinders with low compression.

6. Inspect Vacuum Lines and Intake

1. Visually check all vacuum lines for cracks or disconnections.
2. Use a smoke test or carburetor cleaner to identify leaks around the intake manifold gasket.
3. Replace any damaged vacuum lines or gaskets.