The check engine light kept coming on and I took it to the dealer for repair and was told "it's ok. Forget it." On 01-09-2009 while traveling on Texas highway 60, I had the cruise control set for 70 mph. Traffic was normal but continually passed me as if I was going slower. I pulled over at a convenience store and parked the vehicle. The speedometer registered 45 mph in park. I continued home gauging speed by the other traffic. The vehicle was parked. On 01-14-2009, my wife and daughter were in the vehicle returning from school. The speedometer appeared to be working. At approximately 3:00 pm while driving home, the electric door locks began to lock and unlock themselves. At the same time, the A/C went to maximum heat and high blower. My wife stopped the vehicle and put it in park. The side curtain air bags deployed, striking my daughter in the left temple resulting in a mild concussion. Onstar notified the police of a collision. I contacted the dealer who referred me to GMC customer assistance. The agent told me that this kind of thing happens when traveling too fast and turning too sharp. An investigator was dispatched to gather computer information and determine if there had been a collision. His results were there was no collision and the bags deployed per command from the vehicle control system based on the vehicle traveling 20 mph and turning too sharp. The vehicle was actually traveling 20 mph on a residential street in a straight line. Turning right would have resulted in going through a fence and left would have put the vehicle in a park. GMC refused to investigate the discrepancies between the computer and the driver's account further. I contacted a local GM dealer who has as much concern about this incident as I do. No repairs have been initiated to date as it is unclear what is at fault. Several GM technicians and service managers believe there is a problem with the vehicle control system but are unable to proceed without approval.

- Pampa, TX, USA

The contact stated while driving at 45 mph hit the brakes and the side air bags deployed and knocked him unconscious. He had a friend in the vehicle and he was able to use the emergency brake to stop the vehicle. There was no collision, and he was unsure whether he ran over anything. The roof lining fell because of the air bag deployment. He sustained head abrasions; he could not hear out of left ear, and could not see properly out of left eye. The vehicle was taken to the dealership, and they could not touch the vehicle without a GM engineer's approval. He received a history of vehicle at time of purchase, and has since noticed there had been body work done.

- Brooklyn, NY, USA

Complaint received via E-mail. My wife was in her 2005 GMC Envoy when it was hit on the driver's tire, and was driven into a concrete power pole at 40 mph head on. The power lines were knocked down. Driver's side air bag never deployed, and her head hit the steering, causing a bump on the head, a black eye and a cut lip.

- Jacksonville, FL, USA