why does my Toyota Corolla E140 (2006-2013) feel like it's misfiring

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the negative battery terminal to prevent electrical shorts.
• Allow the engine to cool completely before starting work.

2. Replace Spark Plugs

• Remove the ignition coil or spark plug wires carefully.
• Use a spark plug socket to unscrew and remove the old spark plugs.
• Inspect the condition of the old plugs and replace them with new ones, ensuring they are gapped according to manufacturer specifications (usually around 0.043 inches for a Corolla).
• Reinstall the ignition coils or spark plug wires.

3. Inspect and Replace Ignition Coils (if necessary)

• Remove the ignition coil from the cylinder that registered the misfire (refer to OBD-II codes).
• Test the ignition coil with a multimeter for primary and secondary resistance (consult service manual for specific values).
• If defective, replace the ignition coil with a new one.
• Reinstall the ignition coil and ensure all connections are secure.

4. Check Fuel Injectors

• Use a fuel pressure gauge to check that the fuel pressure is within specifications (usually around 40-50 psi).
• If pressure is low, inspect the fuel filter and pump.
• Clean or replace any clogged fuel injectors using a fuel injector cleaning kit or replace them if necessary.

5. Inspect Air Intake and Vacuum Lines

• Visually inspect the air intake system for cracks or loose connections.
• Check all vacuum hoses for signs of wear or leaks.
• Replace any damaged hoses to ensure proper air intake.