how to fix P0300 misfire code in Toyota Corolla E170 (2013-2019)?

Solution

1. Preparation

• Tools Required: OBD-II scanner, socket set, torque wrench, fuel pressure gauge, multimeter.
• Check the vehicle’s service manual for specific torque values and specifications.
• Ensure the engine is cool and the battery is disconnected.

2. Inspect and Replace Ignition Components

• Sub-steps:
  1. Remove the engine cover if applicable.
  2. Disconnect the electrical connectors from the ignition coils.
  3. Unscrew and remove the ignition coils using a socket set.
  4. Remove the spark plugs using a spark plug socket. Inspect for wear, carbon buildup, or damage.
  5. Replace spark plugs with OEM or recommended aftermarket parts, ensuring the gap is set to specifications.
  6. Install new ignition coils if they are found to be faulty.
  7. Reconnect the electrical connectors to the ignition coils.

3. Fuel System Inspection

• Sub-steps:
  1. Connect a fuel pressure gauge to the fuel rail.
  2. Turn the ignition to the "ON" position (do not start) to check fuel pressure.
  3. Compare the reading with specifications in the service manual. If low, inspect the fuel pump and filter.
  4. Replace the fuel filter if it is clogged or has not been changed per the maintenance schedule.
  5. If necessary, replace the fuel pump.

4. Check for Vacuum Leaks

• Sub-steps:
  1. Inspect all vacuum hoses for cracks, splits, or disconnections.
  2. Using a smoke machine, introduce smoke into the intake system to identify leaks.
  3. Repair or replace any faulty hoses or gaskets.

5. Compression Test

• Sub-steps:
  1. Remove all spark plugs to allow for easier cranking of the engine.
  2. Insert a compression gauge into one cylinder at a time.
  3. Crank the engine several times and record the compression reading.
  4. Repeat for all cylinders and compare results. Replace any cylinder with significantly lower compression.