Chevrolet Volt rough idle and shaking during startup on Chevrolet Volt

Some Chevrolet Volt owners report experiencing rough idle and shaking during startup, which may be attributed to several factors including vacuum leaks, spark plug issues, and ignition coil problems. Additionally, a malfunctioning Idle Air Control (IAC) valve could contribute to these symptoms, as it regulates air intake during idle. It's noteworthy that the Volt lacks an idle stabilizer or idle air control actuator, and the oxygen sensors are inactive for the first few seconds of operation, potentially affecting the startup process. Service updates addressing misfire and rough running at startup have been issued for certain model years, indicating that these concerns are acknowledged by Chevrolet. In colder climates, some owners notice that the gas mode engages automatically, resulting in unusual engine behaviors like loud humming or vibrations during braking. Furthermore, reprogramming the engine control module may be necessary to mitigate engine misfire conditions that can arise after extended periods of inactivity, contributing to rough or high idle. Proper diagnosis and maintenance are essential for resolving these issues effectively.