how to fix P0301 misfire on my Toyota Corolla E210 (2019-2024)

Solution

1. Preparation

• Gather tools and parts.
• Ensure the engine is cool and disconnect the battery to prevent electrical shock.

Tools Required:

• OBD-II scanner
• Socket set
• Torque wrench
• Compression tester
• Multimeter
• Fuel injector cleaner
• Replacement spark plug
• Replacement ignition coil (if needed)
• Replacement fuel injector (if needed)

2. Inspect and Replace Spark Plug

1. Remove the ignition coil cover if applicable.
2. Disconnect the ignition coil connector.
3. Remove the ignition coil from cylinder 1 using a socket.
4. Remove the spark plug using a spark plug socket.
5. Inspect the spark plug for wear; replace if necessary with a new spark plug, ensuring the gap is set to manufacturer specifications (usually around 0.043 inches).
6. Reinstall the ignition coil, securing it with the socket and reconnect the connector.

3. Check and Replace Ignition Coil

1. Use a multimeter to test the ignition coil's primary and secondary resistance against manufacturer specifications.
2. If the ignition coil is faulty, remove it and install a new ignition coil.
3. Torque the ignition coil to the manufacturer’s specifications (usually around 7-10 ft-lbs).

4. Inspect and Clean/Replace Fuel Injector

1. If the injector is suspected of being clogged, remove it from the fuel rail.
2. Use fuel injector cleaner to clean the injector or replace it with a new one if necessary.
3. Reinstall the injector, ensuring proper seating and connection to the fuel rail.

5. Test Compression

1. Remove the spark plug from cylinder 1.
2. Insert the compression tester into the spark plug hole.
3. Crank the engine to obtain a compression reading.
4. Compare the reading to manufacturer specifications (typically around 190-210 psi).
5. If compression is low, further investigation into piston rings or valves may be necessary.