how to fix 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 necessary tools and parts.
• Ensure the engine is cool and disconnect the battery to prevent electrical shock.

2. Replace Spark Plug

• Tools Required: Socket set, torque wrench, gap gauge
• Remove the engine cover if present.
• Use a socket to remove the spark plug from cylinder 1.
• Inspect the spark plug for wear; replace if necessary.
• Check the gap on the new spark plug using a gap gauge, adjust to manufacturer specifications.
• Install the new spark plug and torque it to the manufacturer's specification (typically around 15-20 lb-ft).

3. Replace Ignition Coil

• Tools Required: Socket set
• Locate the ignition coil for cylinder 1.
• Disconnect the electrical connector from the ignition coil.
• Remove the mounting bolts and lift out the ignition coil.
• Install the new ignition coil, securing it with bolts and reconnecting the electrical connector.

4. Inspect Fuel Injector

• Tools Required: Fuel pressure gauge (if testing required)
• Locate the fuel injector for cylinder 1.
• Disconnect the fuel injector connector.
• If needed, test the injector with a multimeter to ensure it has the correct resistance.
• Replace the injector if it is faulty.

5. Address Vacuum Leaks

• Tools Required: Smoke machine or carburetor cleaner
• Inspect hoses connected to the intake manifold and throttle body for cracks or disconnections.
• Use a smoke machine to detect any vacuum leaks; if found, repair or replace the affected hoses.