how to fix a misfire in my Toyota Highlander Third Generation (2014-2019) with code P0302

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Ensure the vehicle is parked on a flat surface, and the engine is cool.
• Disconnect the negative terminal of the battery to prevent electrical shocks.

2. Inspect and Replace Spark Plug

• Remove the engine cover if necessary using a socket set.
• Disconnect the ignition coil connector from cylinder #2.
• Remove the ignition coil from cylinder #2 using a socket wrench.
• Remove the spark plug using a spark plug socket.
• Inspect the spark plug for wear and replace it if necessary with a new one, ensuring it is gapped correctly to manufacturer specifications (typically around 0.044 inches).
• Reinstall the spark plug and torque it to the manufacturer's specification (usually around 13 lb-ft).

3. Inspect and Replace Ignition Coil

• If the spark plug is fine, test the ignition coil with a multimeter to check for proper resistance.
• If faulty, replace the ignition coil for cylinder #2 with a new unit.
• Reassemble the ignition coil and connector, ensuring they are secure.

4. Inspect Fuel Injector

• If misfire persists, disconnect the fuel injector connector for cylinder #2.
• Use a fuel injector tester to check for proper operation. If it’s clogged or malfunctioning, replace it.
• Reconnect the fuel injector and ensure all connections are secure.

5. Final Assembly

• Reconnect the negative terminal of the battery.
• Start the engine and allow it to idle for a few minutes.