GM part number 95027313 outlet duct connecting the air box to the throttle body has shredded in 30,000 miles of use. This problem causes the engine to run lean (odb2 error code P0171) resulting in significantly reduced fuel economy, poor acceleration, rough idle, and potential failures to a number of costly sensors and components, as well as allowing dirty, un-filtered directly into the engine. A quick google search reveals 26,000 search results including forums and message boards where countless Sonic owners report the same issue. This is a widespread product defect and GM needs to provide a repair solution for owners of this model vehicle. The part had deteriorated to the point, where the check engine light illuminated. The consumer noticed the fuel economy of the vehicle dropping steadily from the advertised 29/city/40 highway to an average of about 25 mpg highway.

- South San Francisco, CA, USA