Which diagnostic step is most appropriate to isolate a misfire caused by an ignition component?

Which diagnostic step is most appropriate to isolate a misfire caused by an ignition component?

• A. Misfire persists or improves after swapping suspected ignition coil/plug with a known good part; observe change in misfire behavior.
• B. Replace the fuel pump.
• C. Replace the exhaust sensors.
• D. Reset the engine control unit with a battery disconnect.

Answer: (A)