how to fix a P0303 misfire in my Toyota RAV4 XA40 (2013-2018)

Solution

1. Preparation

• Tools Required: OBD-II scanner, socket set, torque wrench, multimeter, compression tester, fuel injector cleaner.
• Ensure the vehicle is parked on a level surface and the engine is cool.
• Disconnect the negative battery terminal to prevent electrical shock.

2. Inspect and Replace Spark Plug

1. Remove the engine cover if present.
2. Locate the spark plug for cylinder 3.
3. Use a socket and ratchet to remove the spark plug.
4. Inspect the spark plug for wear, carbon buildup, or physical damage.
5. If necessary, replace it with a new spark plug that meets OEM specifications (typically NGK or Denso).
6. Torque the new spark plug to the manufacturer’s specification (usually around 13 lb-ft).

3. Inspect and Replace Ignition Coil

1. Remove the ignition coil from cylinder 3 by disconnecting the electrical connector and unscrewing the mounting bolts.
2. Inspect the ignition coil for any signs of damage or corrosion.
3. If faulty, replace the ignition coil with a new one that matches OEM specifications.
4. Reinstall the ignition coil and reconnect the electrical connector.

4. Check and Clean Fuel Injector

1. Remove the fuel injector from cylinder 3 by detaching any connectors and unscrewing the mounting.
2. Inspect the injector for clogs or physical damage.
3. If necessary, clean the injector using a fuel injector cleaner or replace it with a new one.
4. Reinstall the injector, ensuring proper seating and secure connections.

5. Verify Engine Compression

1. Insert the compression tester into the spark plug hole for cylinder 3.
2. Crank the engine and observe the compression reading.
3. Compare the reading with manufacturer specifications (typically 180-200 psi).
4. If compression is below specifications, further investigation into engine internals may be necessary.