why does my Toyota Corolla E170 (2013-2019) engine misfire after warming up

Solution

1. Preparation

• Gather all necessary tools and parts.
• Ensure the vehicle is parked on a level surface and the engine is cool.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Inspect and Replace Spark Plugs

• Remove the ignition coil covers (if applicable).
• Use a socket wrench to remove the spark plugs.
• Inspect the old spark plugs for signs of wear or fouling; replace if necessary.
• Install new spark plugs, ensuring the gap is set to manufacturer specifications (typically around 0.044 inches).
• Torque the spark plugs to the manufacturer's specifications (usually around 13 lb-ft).

3. Test and Replace Ignition Coils

• Remove the ignition coils from the spark plugs.
• Use a multimeter to test the resistance of each ignition coil according to specifications. Replace any that are out of range.
• Reinstall the ignition coils, securing them properly.

4. Inspect Fuel Injectors

• Use a fuel pressure gauge to check fuel pressure while the engine is running. Refer to the specifications for the correct pressure range.
• If fuel pressure is low, inspect the fuel filter and fuel pump for issues.
• If fuel injectors are suspected to be clogged or malfunctioning, consider cleaning or replacing them.

5. Check for Vacuum Leaks

• Visually inspect hoses and connections in the intake system for any cracks or disconnections.
• Use a smoke machine or carburetor cleaner to detect leaks. Repair or replace any damaged components.

6. Replace Engine Coolant Temperature Sensor (if necessary)

• Locate the coolant temperature sensor; typically found near the thermostat housing.
• Disconnect the electrical connector and remove the sensor using a wrench.
• Install the new sensor, tightening it to the manufacturer's specifications, and reconnect the electrical connector.