how to resolve P0300 random misfire code in Toyota Corolla E210 (2019-2024)?

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Disconnect the negative battery terminal to ensure safety.

2. Inspect and Replace Spark Plugs

• Sub-steps:
  1. Remove the engine cover if applicable.
  2. Disconnect the ignition coils from the spark plugs.
  3. Use a spark plug socket to remove the spark plugs.
  4. Inspect the old spark plugs for wear; replace with OEM or quality aftermarket spark plugs if necessary.
  5. Ensure proper gap settings according to specifications (typically 0.043 inches for Toyota).
  6. Reinstall the spark plugs and reconnect the ignition coils.

3. Inspect and Replace Ignition Coils

• Sub-steps:
  1. Remove the ignition coils from the engine, noting the order of removal.
  2. Use a multimeter to test the resistance of each ignition coil; replace any that are out of specification.
  3. Install new ignition coils securely and reconnect electrical connectors.

4. Test and Replace Fuel Injectors

• Sub-steps:
  1. Use a fuel injector tester to check the operation of each injector.
  2. If any injector is found to be faulty, remove it using a fuel injector removal tool.
  3. Install new fuel injectors, ensuring they are seated properly and secured.

5. Check for Vacuum Leaks

• Sub-steps:
  1. Inspect all vacuum hoses for cracks or disconnections.
  2. Use a smoke machine to identify any hidden leaks.
  3. Replace any damaged hoses and ensure all connections are tight.

6. Perform Engine Compression Test

• Sub-steps:
  1. Remove spark plugs and disable the ignition system.
  2. Insert a compression tester into each cylinder's spark plug hole.
  3. Crank the engine and record compression readings for each cylinder; compare to manufacturer's specifications.
  4. Address any cylinders with low compression through further inspection or repairs.

Tools Required:

• OBD-II scanner
• Spark plug socket
• Torque wrench
• Multimeter
• Fuel injector tester
• Compression tester
• Smoke machine (optional)

Parts Required:

• Spark plugs
• Ignition coils (if faulty)
• Fuel injectors (if faulty)
• Vacuum hoses (if damaged)

Estimated Repair Time: 2-4 hours

Safety Warnings:

• Disconnect battery before working on electrical systems.
• Allow engine to cool before performing any repairs.
• Handle fuel injectors with care to avoid fuel spillage.