Pontiac G6 engine misfire and rough idle with no check engine light on Pontiac G6

Some Pontiac G6 owners report experiencing engine misfire and rough idle without the check engine light being illuminated. These issues may be caused by vacuum leaks in the engine system, which can lead to rough idling. Additionally, worn-out or faulty spark plugs and malfunctioning ignition coils are common culprits that can result in misfires. Problems within the fuel system, such as clogged fuel injectors, may also contribute to these symptoms. Furthermore, faulty engine sensors, including the mass airflow sensor or oxygen sensor, could negatively impact engine performance. To diagnose and resolve these issues, some owners find it helpful to conduct a diagnostic scan for stored error codes, inspect and replace spark plugs, and check ignition coils for damage. Addressing vacuum leaks and ensuring the fuel system is clean are also recommended steps. If problems persist, consulting a mechanic for a comprehensive diagnosis is advisable.