how to troubleshoot the engine misfiring in my Toyota Corolla E170 (2013-2019)

Solution

1. Preparation

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

2. Inspect and Replace Spark Plugs

• Remove the ignition coil cover if applicable.
• Use a socket set to remove the spark plug wires or ignition coils.
• Inspect each spark plug for wear, carbon buildup, or damage.
• Replace any defective spark plugs with OEM or quality aftermarket parts, ensuring the correct gap.
• Reinstall the ignition coils and cover. Torque bolts to manufacturer specifications (typically around 7–10 ft-lbs).

3. Check and Replace Ignition Coils

• If misfire codes indicate a specific cylinder, consider replacing the corresponding ignition coil.
• Remove the faulty ignition coil using a socket set.
• Install a new ignition coil and connect the wiring harness.
• Ensure proper seating and torque to manufacturer specifications.

4. Inspect and Clean Fuel Injectors

• Remove the fuel rail if necessary to access the fuel injectors.
• Check fuel injector operation using a multimeter or a noid light.
• Clean or replace any clogged or defective fuel injectors.
• Reassemble the fuel rail, ensuring all seals are properly seated to prevent leaks.

5. Conduct a Compression Test

• Remove the spark plugs for ease of access.
• Insert a compression gauge into each cylinder and crank the engine.
• Record the compression readings; they should be within manufacturer specifications (typically around 180-200 psi).
• If readings are low, further investigation may be required (e.g., valve issues, head gasket).