how to diagnose a P0301 misfire code on my Toyota Tacoma N300 (2016-Present)

Solution

1. Preparation

• Gather 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. Replace Spark Plug

• Tools Required: Spark plug socket, ratchet, torque wrench.
• Remove the ignition coil for cylinder 1 by unscrewing the bolts and disconnecting the electrical connector.
• Use a spark plug socket to remove the old spark plug.
• Inspect the new spark plug for proper gap settings (usually 0.044 inches for Tacoma).
• Install the new spark plug and torque it to manufacturer specifications (typically 13 lb-ft).
• Reinstall the ignition coil and secure it with bolts.

3. Check and Replace Ignition Coil

• Tools Required: Multimeter, socket set.
• Using a multimeter, check the resistance of the ignition coil. Compare the readings to the manufacturer’s specifications.
• If the coil is faulty, disconnect the electrical connector and remove the coil.
• Install the new ignition coil and reconnect the electrical connector.

4. Clean or Replace Fuel Injector

• Tools Required: Fuel injector cleaner, compression gauge (if testing injector function).
• Remove the fuel injector from cylinder 1 by unscrewing the retaining clips and disconnecting the fuel line.
• Clean the injector using an appropriate fuel injector cleaner or replace it if it’s defective.
• Reinstall the fuel injector and ensure it is securely connected.

5. Compression Test

• Tools Required: Compression tester.
• Remove the spark plug from cylinder 1 and install the compression tester.
• Crank the engine and record the compression reading.
• Compare the reading to the manufacturer’s specifications (typically around 180 psi). Low compression may indicate a deeper engine issue.