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This is a common problem on the Envoy 4.2 engine. No need to replace the compressor.
The problem is that the engine idle speed is dropping too low due to carbon buildup in the throttle body. Remove the air intake tube and resonator box in front of the throttle body on top of the engine. Then use carburetor cleaner spray to clean the throttle body (throttle blade and bore). This will allow more airflow at closed throttle and will prevent the engine from stalling.

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There are throttle body cleaner sprays that you can purchase. Plain carburetor cleaner spray works well and is likely cheaper. This is available at most parts stores and at walmart.