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

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Disconnect the negative battery terminal to ensure safety.
• Allow the engine to cool down before proceeding with any work.

2. Inspect and Replace Ignition Components

• Tools Required: Socket set, torque wrench, pliers.
• Inspect the spark plug in cylinder 1:
  • Remove the ignition coil by unbolting it and gently pulling it out.
  • Remove the spark plug using a spark plug socket.
  • Inspect for wear, carbon buildup, or damage.
  • If necessary, replace the spark plug with a new one (gapping per manufacturer specifications).
• Test the ignition coil:
  • Use a multimeter to check coil resistance.
  • If the coil is out of specification, replace it with a new one.

3. Check Fuel Injector

• Tools Required: Fuel pressure gauge, socket set.
• Locate the fuel injector for cylinder 1:
  • Disconnect the fuel line (ensure a rag is used to catch any fuel spills).
  • Remove the fuel injector wiring harness.
  • Check for clogs or leaks in the injector.
  • If defective, replace the fuel injector.
• Reconnect fuel lines and wiring.

4. Compression Testing

• Tools Required: Compression tester.
• Perform a compression test:
  • Remove the spark plug from cylinder 1.
  • Insert the compression tester and crank the engine several times.
  • Record the compression reading; compare it to manufacturer specifications.
  • If compression is low, further investigation into valve or piston condition may be required.

5. Reassembly

• Reinstall all components in reverse order.
• Ensure all bolts are tightened to manufacturer specifications.
• Reconnect the negative battery terminal.