* Idle Air Control (IAC) valve: The IAC valve is responsible for controlling the amount of air that bypasses the throttle body, and it can cause a rough idle if it's not working properly.
* Mass Air Flow (MAF) sensor: The MAF sensor measures the amount of air entering the engine, and it can cause a rough idle if it's dirty or damaged.
* Throttle body: The throttle body controls the amount of air that flows into the engine, and it can cause a rough idle if it's dirty or damaged.
* Spark plugs: Spark plugs that are worn out or dirty can cause a rough idle.
* Vacuum leaks: Vacuum leaks can cause a lean fuel mixture, which can lead to a rough idle.
If you're not sure what's causing your GM Envoy to idle rough, it's best to take it to a qualified mechanic for diagnosis and repair.
