2007 Pontiac G6 GT convertible 3.9 V6 malfunction of exhaust system behind the catalytic converters causes a loud whistle at 2-3K RPM and reduction in performance and fuel efficiency. This is a known issue and reported on the internet with this particular sport exhaust on this model and engine. It begins at approximately 50K miles. The GM dealer nor Pontiac will address and fix. Cost of repair to consumer, $1500. Only solution is to replace exhaust assembly from the flex pipe back.

- Sunland, CA, USA

Dropped my car off for service at the dealership and they later called to say the engine had caught fire when they were test driving the car. An inspector from the insurors service bureau determined that a "rodent infestation" was the cause and that a nest had been built in the exhaust header. I have since seen several other owners reporting fires in the engine compartment and believe there might be a design defect that allows animals access to an internal location where engine heat ignites their nesting material.

- Smithfield, RI, USA