how to fix P0301 misfire code in 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 necessary tools and parts.
• Disconnect the negative battery terminal to prevent electrical shorts.
• Allow the engine to cool before starting work.

2. Inspect and Replace Spark Plug

• Sub-steps:
  1. Remove the engine cover (if applicable) to access the spark plug.
  2. Using a socket wrench, remove the spark plug from Cylinder 1.
  3. Inspect the spark plug for wear, carbon buildup, or damage.
  4. Replace the spark plug with a new one (use OEM specifications).
  5. Torque the new spark plug to the manufacturer's specifications (typically around 13 lb-ft).

3. Check and Replace Ignition Coil

• Sub-steps:
  1. Disconnect the ignition coil connector.
  2. Remove the ignition coil from Cylinder 1.
  3. Inspect the coil for cracks or burn marks.
  4. Replace with a new ignition coil if damaged.
  5. Reconnect the ignition coil connector securely.

4. Inspect and Test Fuel Injector

• Sub-steps:
  1. Disconnect the fuel injector connector for Cylinder 1.
  2. Use a multimeter to check the resistance of the fuel injector (should be within manufacturer specifications).
  3. If the injector is faulty, remove it from the intake manifold.
  4. Replace with a new fuel injector if necessary, ensuring proper sealing.
  5. Reconnect the fuel injector connector.

5. Compression Test (if necessary)

• Sub-steps:
  1. Remove the spark plug from Cylinder 1 again.
  2. Insert a compression gauge into the spark plug hole.
  3. Crank the engine for a few seconds to get a reading.
  4. Compare the compression reading with manufacturer specifications (should be around 120-180 psi).
  5. If the compression is low, further diagnostics on the engine may be required.