how to resolve a P0302 misfire code on my BMW X3 F25 (2011-2018)?

Solution

1. Preparation

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

2. Inspect and Replace Spark Plug

• Remove the engine cover if applicable.
• Use a spark plug socket to remove the spark plug from cylinder 2.
• Inspect the spark plug for signs of wear, carbon buildup, or damage.
• If necessary, replace the spark plug with an OEM equivalent, ensuring the gap is set to the manufacturer's specifications (typically around 0.032 inches).
• Reinstall the spark plug and torque to the manufacturer's specification (usually about 15 ft-lbs).

3. Inspect and Replace Ignition Coil

• Disconnect the electrical connector from the ignition coil in cylinder 2.
• Remove the ignition coil by pulling it straight out of the spark plug well.
• Inspect the coil for cracks or damage. If faulty, replace it with a new OEM ignition coil.
• Reinstall the ignition coil, ensuring proper seating, and reconnect the electrical connector.

4. Check Fuel Injector

• Locate the fuel injector for cylinder 2.
• Disconnect the fuel injector electrical connector.
• Use a multimeter to check the resistance of the injector (should typically be around 12-16 ohms).
• If the injector is faulty, replace it with a new OEM fuel injector.
• Reconnect the electrical connector after replacement.

5. Compression Test

• Remove the spark plug from cylinder 2.
• Install a compression tester in the spark plug hole.
• Crank the engine and record the compression reading. Compare it to the manufacturer's specifications (usually around 140-180 psi).
• If compression is low, further investigation of the piston rings, valves, or head gasket may be necessary.

6. Final Assembly

• Reassemble any components that were removed during inspection.
• Reconnect the negative battery terminal.