how to fix P0301 misfire code in my Toyota Camry XV40 (2007-2011)

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Disconnect the negative battery terminal to prevent electrical shorts.
• Allow the engine to cool down before beginning work.

2. Replace Spark Plug

• Remove the ignition coil from cylinder one by unscrewing the bolts and disconnecting the electrical connector.
• Remove the spark plug using a socket wrench. Inspect for signs of wear or fouling.
• Install a new spark plug, ensuring it is gapped correctly to manufacturer specifications (typically around 0.043 inches for a Camry).
• Reattach the ignition coil, securing it with bolts and reconnecting the electrical connector.

3. Replace Ignition Coil

• If the spark plug replacement does not resolve the issue, proceed to replace the ignition coil.
• Remove the coil as described in the previous step.
• Install a new ignition coil and ensure it is seated properly.
• Reconnect the electrical connector.

4. Check Fuel Injector

• If misfire persists, check the fuel injector for cylinder one.
• Remove the fuel injector connector and test with a noid light to ensure it has power.
• If there is no power, check wiring and connectors for issues. If the injector is faulty, replace it.

5. Compression Test

• If all else fails, perform a compression test on cylinder one.
• Remove the spark plug and insert a compression gauge.
• Crank the engine and record the compression reading. Compare it to the manufacturer's specifications (typically around 180-210 psi for a healthy engine).
• If the compression is low, further diagnosis may be needed for internal engine problems.