my Toyota Corolla E210 (2019-2024) engine is misfiring what are the common causes

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the negative battery terminal to prevent electrical shorts.
• Allow the engine to cool if it has been running.

2. Replace Spark Plugs

• Tools Required: Socket set, torque wrench, spark plug socket.
• Remove the ignition coils to access the spark plugs.
• Use a spark plug socket to remove the old spark plugs.
• Inspect the spark plug gap and install new spark plugs to the manufacturer's specifications (typically 0.044 inches).
• Reinstall the ignition coils and reconnect any electrical connectors.

3. Inspect and Replace Ignition Coils

• Tools Required: Socket set, multimeter, torque wrench.
• Remove the ignition coils from the cylinder head.
• Use a multimeter to test the primary and secondary resistance of the coils (refer to the service manual for specifications).
• Replace any faulty ignition coils with new ones and torque to specifications.

4. Clean or Replace Fuel Injectors

• Tools Required: Fuel injector cleaning kit or replacement injectors, safety glasses, gloves.
• Remove fuel injectors from the engine.
• Clean injectors using a cleaning kit or replace them if they are faulty.
• Reinstall injectors and ensure proper sealing.

5. Check and Repair Vacuum Leaks

• Tools Required: Smoke machine or carburetor cleaner, inspection tools.
• Inspect all vacuum hoses for cracks or disconnections.
• Use a smoke machine to detect any leaks in the intake manifold.
• Replace any damaged hoses or gaskets as necessary.

6. Test Fuel Pressure

• Tools Required: Fuel pressure gauge.
• Connect the fuel pressure gauge to the fuel rail.
• Turn the ignition to the "ON" position (do not start) and check the pressure reading.
• If pressure is below specifications, check the fuel pump and filter for issues.