how to fix a P0301 misfire code on my BMW 3 Series F30/F31 (2012-2019)?

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Disconnect the battery to avoid electrical shorts.
• Allow the engine to cool before beginning work.

2. Replace Spark Plug

• Tools Required: Socket set, torque wrench, anti-seize compound
• Remove the ignition coil by unscrewing the bolt and gently pulling it out.
• Unscrew the spark plug using a spark plug socket.
• Inspect the old spark plug for wear; replace if necessary.
• Apply a small amount of anti-seize compound on the threads of the new spark plug.
• Install the new spark plug, tightening it to the manufacturer's specified torque (typically 22 lb-ft for BMW spark plugs).
• Reconnect the ignition coil.

3. Replace Ignition Coil (if necessary)

• If the ignition coil appears damaged, remove it as done in step 2.
• Install the new ignition coil and secure it with the bolt.
• Ensure the electrical connector is properly seated.

4. Inspect and Replace Fuel Injector (if necessary)

• Tools Required: Fuel line disconnect tool
• Disconnect the fuel line from the injector.
• Remove the fuel injector by unscrewing it from the rail.
• Inspect the injector for clogs or damage; replace if necessary.
• Install the new injector and reconnect the fuel line.

5. Perform Compression Test (if necessary)

• If misfire persists, conduct a compression test on cylinder 1.
• Remove the spark plug and insert the compression tester.
• Crank the engine and record the compression reading; it should be within the manufacturer’s specifications (typically 120-180 psi).
• If compression is low, further investigation into mechanical issues (e.g., valve problems) will be necessary.