how to fix the engine misfire in my BMW X5 F15 (2014-2019) with P0300 code?

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Disconnect the battery to ensure safety while working on the electrical components.
• Allow the engine to cool down before starting any work.

2. Inspect and Replace Ignition Components

• Tools Required: Socket set, torque wrench, spark plug socket, dielectric grease
• Remove the engine cover (if applicable).
• Disconnect the electrical connectors from the ignition coils.
• Remove the ignition coils using a socket wrench.
• Inspect the spark plugs; if worn or fouled, remove them with a spark plug socket and replace them. Check the gap using a spark plug gap tool.
• Apply dielectric grease to the terminals of the new ignition coils and install them.
• Reconnect the electrical connectors to the ignition coils.

3. Fuel System Inspection

• Tools Required: Fuel pressure gauge, safety glasses
• Locate the fuel rail and connect the fuel pressure gauge.
• Turn the ignition to the "ON" position (do not start the engine) to check the fuel pressure; refer to the vehicle specifications for the correct pressure values.
• If pressure is low, inspect the fuel filter and fuel pump for functionality. Replace any faulty components.

4. Check for Vacuum Leaks

• Tools Required: Smoke machine or carburetor cleaner
• Use a smoke machine to introduce smoke into the intake system or spray carburetor cleaner around vacuum lines and gaskets while the engine is running.
• Observe for any changes in engine RPM, indicating a vacuum leak. Repair or replace any damaged hoses or gaskets.

5. Compression Test

• Tools Required: Compression tester
• Remove the spark plugs again for access.
• Insert the compression tester into each cylinder and crank the engine to take readings.
• Compare the readings against the manufacturer’s specifications. If any cylinder shows low compression, further investigation is required.