how to fix the engine misfire in my Toyota Highlander XU70 (2020-Present) with code P0302?

Solution

1. Preparation

• Tools Required: OBD-II scanner, spark plug socket, torque wrench, multimeter, compression tester, fuel injector cleaner.
• Disconnect the negative terminal of the battery to prevent any electrical issues while working on the vehicle.
• Ensure the engine is cool before starting the repair.

2. Replace Spark Plug

• Sub-steps:
  1. Remove the engine cover if applicable.
  2. Disconnect the ignition coil connector for cylinder 2.
  3. Remove the ignition coil by unbolting it (typically a single bolt).
  4. Unscrew the spark plug using a spark plug socket.
  5. Inspect the old spark plug for wear and replace it with a new one, ensuring it is gapped correctly (refer to owner's manual for specifications).
  6. Reinstall the ignition coil and reconnect the connector.

3. Test and Replace Ignition Coil (if necessary)

• Sub-steps:
  1. Use a multimeter to test the resistance of the ignition coil. Compare readings against manufacturer specifications.
  2. If out of spec, remove the ignition coil and replace it with a new one.
  3. Reinstall it onto the spark plug and reconnect the harness.

4. Inspect and Clean Fuel Injector

• Sub-steps:
  1. If the issue persists after replacing the spark plug and ignition coil, remove the fuel injector for cylinder 2.
  2. Check the electrical connector for corrosion or damage.
  3. Clean the injector using a fuel injector cleaning kit or replace it if needed.
  4. Reinstall the fuel injector and ensure all connections are secure.

5. Compression Test

• Sub-steps:
  1. Remove the spark plug from cylinder 2 and insert the compression tester into the spark plug hole.
  2. Crank the engine for a few seconds while monitoring the gauge.
  3. Compare the reading to the manufacturer's specification. If low, further inspection of the engine internals may be required.