Rough, Unstable, or Incorrect Idle and Stalling

WARNING: This page is about a different car, the 2010 Pontiac G5 and 2010 Chevrolet Cobalt. However, it is still accessible from the selected car via links, so may be relevant.

Observe the TB Idle Air Flow Compensation parameter with a scan tool. A value greater than 80 % may indicate an excessive accumulation of deposits in the throttle bore. Inspect the throttle body and clean, if necessary. Refer to Throttle Body Cleaning .
Inspect the MAF sensor for obstruction, contamination, and damage. Refer to Mass Airflow Sensor with Intake Air Temperature Sensor Replacement .
Inspect the engine mounts. Refer to Engine Mount Inspection .
Inspect the intake and exhaust manifolds for casting flash.