how do I address the P0301 misfire code in 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 all necessary tools and parts.
• Disconnect the battery to prevent any electrical shorts.
• Allow the engine to cool down before starting work.

2. Replace Spark Plug

• Tools Required: Socket set, torque wrench, spark plug socket.
• Remove the ignition coil from cylinder 1 by unscrewing the bolts and disconnecting the electrical connector.
• Use the spark plug socket to remove the old spark plug.
• Inspect the spark plug threads for damage.
• Install a new spark plug, ensuring it is gapped correctly (consult specifications for gap size).
• Torque the spark plug to the manufacturer's specification (typically around 15 lb-ft).
• Reinstall the ignition coil and reconnect the electrical connector.

3. Inspect and Replace Ignition Coil (if necessary)

• If the ignition coil is found to be faulty during testing, remove it as described in step 2.
• Replace with a new ignition coil that matches OEM specifications.
• Reconnect the electrical connector and torque any securing bolts.

4. Check and Clean Fuel Injector

• Disconnect the fuel line (use caution and a rag to catch any fuel).
• Remove the fuel injector from cylinder 1.
• Inspect for debris or clogging; clean or replace the injector as necessary.
• Reinstall the fuel injector and reconnect the fuel line securely.

5. Perform Compression Test (if misfire persists)

• Reconnect the battery and start the engine.
• Remove the spark plug from cylinder 1.
• Insert a compression gauge into the spark plug hole and crank the engine.
• Record the compression reading; it should be within the manufacturer's specifications.
• If low, further investigation may be needed for internal engine issues.