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 tools and parts required.
• Ensure the vehicle is parked on a level surface and the engine is cool.
• Disconnect the battery to prevent any electrical shorts.

2. Inspect and Replace Spark Plug

• Tools Required: Socket set, torque wrench, gap gauge.
• Remove the ignition coil cover if present.
• Disconnect the ignition coil connector and remove the coil using a socket.
• Remove the spark plug using a socket and inspect it for wear or fouling.
• If necessary, replace the spark plug with a new one, ensuring it is gapped correctly according to manufacturer specifications.
• Reinstall the ignition coil and reconnect the connector.

3. Test and Replace Ignition Coil

• Tools Required: Multimeter.
• Using a multimeter, test the resistance of the ignition coil for cylinder 1.
• If out of specification, replace the ignition coil with a new one.
• Reinstall the ignition coil and reconnect the connector.

4. Inspect and Replace Fuel Injector

• Tools Required: Noid light, fuel injector removal tool.
• Disconnect the fuel injector connector and test with a noid light to check for signal.
• If there’s no signal, inspect the wiring; if the injector is faulty, replace it.
• Remove the old fuel injector using the fuel injector removal tool and install the new injector, ensuring proper seating and connection.

5. Compression Test

• Tools Required: Compression gauge.
• Remove the spark plug from cylinder 1.
• Insert the compression gauge and crank the engine.
• Record the compression reading and compare it to the manufacturer’s specifications.
• If compression is low, further investigation into the engine internals may be necessary.