Chevrolet Sonic rough idling issue after valve cover gasket and emissions control valve replacements on Chevrolet Sonic

Some Chevrolet Sonic owners report experiencing rough idling issues after replacing the valve cover gasket and emissions control valve. These problems may be linked to the need for fuel injector cleaning to restore proper fuel pressure and improve idling smoothness. Additionally, some owners find that ensuring the engine's mechanical soundness is crucial, as major mechanical problems can exacerbate rough idling. Following systematic diagnostic steps is recommended to identify the underlying causes of the issue. If the problem is related to the 1.4t engine, some owners may benefit from warranty coverage for the replacement of the valve cover with the integrated PCV valve and potentially the wastegate actuator pin. Furthermore, replacing spark plugs during the troubleshooting process is advised, as is addressing any concerns with the PCV valve, since neglecting these can lead to the need for a complete valve cover replacement. Lastly, while a bad valve cover gasket may contribute to power loss, it is important for owners to correctly diagnose the issue, as other underlying problems may also affect engine performance.