how to diagnose a misfire in my Toyota Camry XV70 (2018-2024) with code P0301?

Solution

1. Preparation

• Gather tools: OBD-II scanner, spark plug socket, multimeter, fuel injector cleaner, compression gauge.
• Ensure the engine is cool and disconnect the battery to avoid electrical shorts.

2. Replace Spark Plug

• 1.1 Remove the engine cover if applicable using a socket set.
• 1.2 Use a spark plug socket to remove the spark plug from cylinder 1.
• 1.3 Inspect the old spark plug; replace with a new spark plug (ensure it matches OEM specifications).
• 1.4 Torque the new spark plug to 13 lb-ft (17.6 Nm).
• 1.5 Reinstall the engine cover.

3. Test/Replace Ignition Coil

• 3.1 Disconnect the electrical connector from the ignition coil of cylinder 1.
• 3.2 Remove the ignition coil using a socket set.
• 3.3 Test the ignition coil with a multimeter; check for resistance according to manufacturer specifications (typically 0.5-1.5 ohms).
• 3.4 If faulty, replace with a new ignition coil and reinstall.

4. Inspect/Replace Fuel Injector

• 4.1 Disconnect the fuel injector connector and remove the fuel rail if necessary.
• 4.2 Clean the injector using a fuel injector cleaner or replace if clogged.
• 4.3 Reinstall the fuel injector and reconnect the electrical connector.

5. Conduct Compression Test

• 5.1 Remove the spark plug from cylinder 1 again.
• 5.2 Insert the compression gauge into the spark plug hole.
• 5.3 Crank the engine several times to get a reading. Compare the compression value to manufacturer specifications (typically around 180-210 psi).
• 5.4 If low, further investigation of valve train or piston rings may be necessary.