how to fix P0300 random misfire code on my Genesis G70 IG (2017-2023)

Solution

1. Preparation

• Tools Required: OBD-II scanner, socket set, torque wrench, multimeter, fuel pressure gauge, vacuum gauge.
• Disconnect the negative battery terminal.
• Ensure the engine is cool before starting work.

2. Replace Spark Plugs

• Sub-steps:
  1. Remove the engine cover if applicable.
  2. Disconnect the ignition coils from the spark plugs.
  3. Use a spark plug socket to carefully remove the old spark plugs.
  4. Inspect the old plugs for wear; replace with new spark plugs, ensuring they are gapped correctly according to the manufacturer's specifications.
  5. Torque the new spark plugs to the manufacturer's specifications (usually around 13-15 lb-ft).

3. Inspect and Replace Ignition Coils

• Sub-steps:
  1. After removing the spark plugs, visually inspect ignition coils for cracks or damage.
  2. Use a multimeter to test the resistance of the ignition coils; replace any coils that are out of specification.
  3. Install new ignition coils by pushing them into place over the new spark plugs until they click.

4. Check and Adjust Fuel System

• Sub-steps:
  1. Connect the fuel pressure gauge to the fuel rail and turn the ignition on (do not start the engine) to check fuel pressure.
  2. If pressure is below specification, inspect the fuel filter and fuel pump for clogs or failure; replace if necessary.
  3. Reconnect all components after testing.

5. Inspect Air Intake and Vacuum System

• Sub-steps:
  1. Check the air intake duct for any cracks or loose fittings; replace any damaged components.
  2. Use a vacuum gauge to test for any vacuum leaks; repair any leaks found in hoses or intake gaskets.
  3. Reassemble any components removed during inspection.