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 necessary tools and parts.
• Ensure the vehicle is parked on a flat surface and the engine is cool.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Replace Spark Plug

• Tools Required: Socket set, torque wrench, spark plug socket, anti-seize compound.
• Remove the engine cover if applicable.
• Use the spark plug socket to remove the spark plug from cylinder 1.
• Inspect the old spark plug for wear or carbon buildup.
• Apply anti-seize compound to the threads of the new spark plug.
• Torque the new spark plug to the manufacturer's specifications (usually around 15 lb-ft).
• Reinstall the engine cover if removed.

3. Inspect and Replace Ignition Coil

• Tools Required: Socket set, multimeter.
• Remove the ignition coil connector by pressing the tab and pulling it off.
• Use a socket to remove the ignition coil from cylinder 1.
• Test the ignition coil with a multimeter for proper resistance as per specifications.
• If faulty, replace the ignition coil with a new one.
• Reinstall the ignition coil and reconnect the connector.

4. Check Fuel Injector

• Tools Required: Fuel pressure gauge, injector cleaner (optional).
• Disconnect the fuel injector connector.
• Use a fuel pressure gauge to check the fuel pressure at the rail.
• If low, check the fuel pump and filter; replace as necessary.
• If the fuel injector is suspected to be faulty, remove it and clean it or replace it.
• Reconnect the fuel injector and its connector.

5. Compression Test (If Necessary)

• Tools Required: Compression tester.
• Remove the spark plug from cylinder 1.
• Insert the compression tester into the spark plug hole.
• Crank the engine and note the compression reading.
• Compare the reading to manufacturer specifications. If low, further diagnosis may be needed for potential internal engine issues.