how to fix my Jaguar XF X260 (2015-2024) with a P0302 misfire code?

Symptoms

• Check engine light illuminated
• Rough idle when the engine is running
• Reduced engine power
• Poor fuel economy
• Engine stalling or hesitation during acceleration

Diagnostic Steps

1. Scan for error codes using an OBD-II scanner to confirm the P0302 code.
2. Inspect the ignition system components (spark plug, ignition coil) for damage or wear.
3. Check the fuel injector for cylinder 2 for proper operation.
4. Perform a compression test on cylinder 2 to rule out mechanical issues.
5. Inspect vacuum hoses and intake manifold for leaks that could affect cylinder performance.
6. Check the engine coolant temperature sensor and mass airflow sensor for proper function.

Solution

1. Preparation

• Gather all necessary tools and parts.
• Ensure the vehicle is parked on a level surface and the engine is cool.
• Disconnect the negative battery terminal.

2. Inspect and Replace Spark Plug

• Tools Required: Socket set, torque wrench, spark plug socket.
• Remove the engine cover if applicable.
• Using a socket wrench, remove the spark plug from cylinder 2.
• Inspect the spark plug for wear, carbon buildup, or damage.
• Replace with a new spark plug, ensuring it is gapped correctly according to specifications (typically around 0.028-0.031 inches).
• Torque the new spark plug to the manufacturer’s specifications (usually around 13-15 lb-ft).

3. Inspect and Replace Ignition Coil

• Tools Required: Socket set, multimeter.
• Disconnect the electrical connector from the ignition coil on cylinder 2.
• Remove the ignition coil using a socket wrench.
• Test the ignition coil using a multimeter to ensure it is functioning correctly (check for resistance).
• If faulty, replace with a new ignition coil and reattach.

4. Check and Clean Fuel Injector

• Tools Required: Fuel injector cleaning kit or replacement injector.
• Disconnect the fuel line and electrical connector from the fuel injector for cylinder 2.
• Remove the fuel injector using a socket wrench.
• Inspect for clogs or damage; if dirty, clean with a fuel injector cleaning solution.
• If necessary, replace with a new injector and reconnect.

5. Perform Compression Test

• Tools Required: Compression gauge.
• Remove spark plug from cylinder 2 and install the compression gauge.
• Crank the engine and record the compression reading.
• Compare the reading to the manufacturer's specifications; a low reading may indicate internal engine problems.

6. Reassemble and Test

• Reinstall any components removed during the repair.
• Reconnect the negative battery terminal.
• Start the engine and allow it to reach operating temperature.