why does my BMW 3 Series F30/F31 (2012-2019) have a P0301 misfire code

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Disconnect the negative battery terminal to ensure safety while working.
• Allow the engine to cool before beginning any work.

2. Inspect and Replace Spark Plug

• Remove the ignition coil for cylinder 1:
  • Unscrew any retaining bolts.
  • Carefully lift the ignition coil straight out of the spark plug well.
• Remove the spark plug:
  • Use a spark plug socket and ratchet to carefully unscrew and remove the spark plug.
  • Inspect the spark plug for signs of wear or fouling.
• Install a new spark plug:
  • Ensure the new spark plug has the correct gap as per manufacturer specifications (usually around 0.030 inches).
  • Apply anti-seize compound on the threads (if recommended).
  • Torque the new spark plug to the manufacturer-specified value (typically around 18 lb-ft).

3. Inspect and Replace Ignition Coil

• If the ignition coil is found to be faulty:
  • Install a new ignition coil for cylinder 1.
  • Ensure proper seating of the coil onto the new spark plug.
  • Reconnect the electrical connector securely.

4. Check Fuel Injector

• If necessary, remove the fuel injector for cylinder 1:
  • Disconnect the electrical connector and fuel line (ensure to relieve fuel pressure beforehand).
  • Use appropriate tools to remove the injector from the rail.
• Inspect or replace the fuel injector if it appears clogged or damaged.

5. Reassemble and Reconnect

• Reinstall the ignition coil and any components removed during the process.
• Reconnect the negative battery terminal.