how to fix a BMW 5 Series F10/F11 (2010-2017) with a P0301 misfire code?

Solution

1. Preparation

• Gather all necessary tools and parts.
• Disconnect the negative battery terminal to ensure safety during repairs.

2. Inspect and Replace Spark Plug

• Tools Required: Spark plug socket, torque wrench, dielectric grease.
• Remove the engine cover if necessary.
• Locate and remove the spark plug wire or ignition coil for cylinder 1.
• Use a spark plug socket to remove the spark plug from cylinder 1.
• Inspect the spark plug for wear or damage; replace if necessary.
• Install the new spark plug, ensuring it is gapped correctly (refer to manufacturer specifications).
• Torque the spark plug to the specified value (typically around 18-22 ft-lbs).
• Apply dielectric grease to the ignition coil or spark plug wire before reinstallation.

3. Inspect and Replace Ignition Coil

• Tools Required: Socket set.
• Remove the ignition coil for cylinder 1 by unscrewing the retaining bolts.
• Inspect the ignition coil for cracks or signs of wear; replace if necessary.
• Install the new ignition coil and secure it with the retaining bolts to the specified torque.

4. Check and Replace Fuel Injector

• Tools Required: Fuel injector removal tool, shop towel.
• Disconnect the fuel line and electrical connector from the fuel injector.
• Remove the old fuel injector from cylinder 1 by unscrewing it from the intake manifold or rail.
• Inspect the fuel injector for clogs; clean or replace it as necessary.
• Install the new fuel injector, ensuring it is seated correctly.

5. Compression Test (if required)

• Tools Required: Compression tester.
• Remove all spark plugs for easier access.
• Insert the compression tester into the spark plug hole of cylinder 1.
• Crank the engine to take a compression reading and compare with manufacturer specifications (typically around 150-200 psi).
• If compression is low, further diagnosis is needed for potential internal engine issues.