how to fix a misfiring engine in my Toyota Tacoma N300 (2016-Present)

Learn how to diagnose and fix engine misfire issues (P0300-P0306) in Toyota Tacoma N300. Step-by-step guide with diagnostic procedures and repair instructions.

Solution

1. Preparation

• Gather tools: OBD-II scanner, multimeter, socket set, torque wrench, compression tester, and cleaning supplies.
• Disconnect the negative battery terminal to prevent electrical shorts and ensure safety.

2. Replace Spark Plugs

• Sub-steps:
  1. Remove the engine cover if applicable (use socket set).
  2. Disconnect the ignition coils by removing the electrical connectors.
  3. Remove the ignition coils using a socket set.
  4. Unscrew and remove the old spark plugs using a spark plug socket.
  5. Inspect and clean the spark plug ports to prevent debris from entering the combustion chamber.
  6. Install new spark plugs (set gap according to manufacturer specifications).
  7. Reinstall the ignition coils and connect the electrical connectors.

3. Check and Replace Ignition Coils (if necessary)

• Sub-steps:
  1. Use a multimeter to test the primary and secondary resistance of each ignition coil.
  2. If any coil is out of specification, remove it using a socket set.
  3. Install new ignition coils and ensure they are seated properly.

4. Inspect and Clean Fuel Injectors

• Sub-steps:
  1. Remove the fuel rail by disconnecting fuel lines and bolts (use caution to avoid fuel spillage).
  2. Remove the fuel injectors from the rail.
  3. Clean the injectors using a fuel injector cleaning kit or replace them if necessary.
  4. Reassemble the fuel rail and reconnect all lines securely.

5. Conduct Compression Test

• Sub-steps:
  1. Remove spark plugs and connect the compression tester to each cylinder.
  2. Crank the engine and record compression readings for each cylinder.
  3. Compare readings; if any cylinder is significantly lower, further investigation may be needed (e.g., valves, piston rings).