how to fix P0301 misfire code on my GMC Sierra T1XX (2019-Present)

Learn how to diagnose and fix P0301 cylinder 1 misfire in GMC Sierra T1XX. Step-by-step guide with diagnostic procedures and repair instructions.

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Disconnect the negative battery terminal to ensure safety.
• Allow the engine to cool down completely before starting any work.

2. Replace Spark Plug

• Remove the engine cover if applicable.
• Use a socket set to remove the spark plug from cylinder one.
  • Tools Required: Socket wrench, spark plug socket, torque wrench.
  • Safety Warning: Avoid touching hot engine components.
• Inspect the old spark plug for signs of wear or fouling.
• Install a new spark plug, ensuring it is gapped correctly according to manufacturer specifications.
• Torque the spark plug to the recommended value (typically around 13-15 lb-ft).

3. Replace Ignition Coil

• Disconnect the electrical connector from the ignition coil for cylinder one.
• Remove the mounting bolts securing the ignition coil and take it out.
• Install the new ignition coil and secure it with bolts.
• Reconnect the electrical connector.

4. Test/Fix Fuel Injector

• If the injector is faulty, remove the fuel rail to access the injector for cylinder one.
• Disconnect the fuel line and electrical connector from the injector.
• Replace the faulty injector with a new one.
• Reinstall the fuel rail and ensure all connections are secure.

5. Reassemble and Reconnect

• Reconnect any components or engine covers that were removed.
• Reconnect the negative battery terminal.