how to fix a misfire issue in Toyota Highlander XU70 (2020-Present)

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, dielectric grease.
• Remove the engine cover if applicable.
• Disconnect the ignition coils from the spark plugs.
• Use a spark plug socket to remove the old spark plugs.
• Inspect and clean the spark plug wells; apply dielectric grease to the new spark plug threads.
• Install new spark plugs, tightening them to the manufacturer’s specified torque (typically 13-15 lb-ft).
• Reconnect the ignition coils.

3. Test and Replace Ignition Coils (if necessary)

• Tools Required: Multimeter, torque wrench.
• Disconnect the ignition coil connectors and remove the coils from the spark plugs.
• Use a multimeter to test the primary and secondary resistance of each coil; refer to manufacturer specifications.
• If a coil is faulty, replace it with a new one, ensuring it is torqued to the specified value (usually around 80-100 lb-in).
• Reconnect the ignition coils.

4. Inspect and Clean Fuel Injectors

• Tools Required: Fuel injector cleaning kit, safety glasses, gloves.
• Remove the fuel rail from the engine, taking care to relieve any fuel pressure beforehand.
• Disconnect the fuel injectors from the rail.
• Use a fuel injector cleaning kit to clean the injectors, following the manufacturer’s instructions.
• Reinstall the injectors in the rail and reconnect them.

5. Final Assembly

• Reinstall the fuel rail and any components removed during the process.
• Reconnect the negative battery terminal.
• Start the engine and check for any leaks or unusual noises.