2007 Suburban vehicle came to a stop 25ft behind several stopped cars at a red light. Without provocation, the vehicle strongly accelerated/surged forward while the brakes were engaged. Driver continued to attempt to stop the vehicle by repeatedly hitting the brake pedal, but with no success. Passenger in vehicle reported seeing drivers foot on the brake. Vehicle accelerated forward into the back of another vehicle which was then pushed into a third. All three vehicles suffered damage. Airbags failed to deploy in Suburban despite level of impact. Vehicle was taken to Chevrolet dealer for complete diagnostic. Results inconclusive; no data errors recorded in computers and no apparent mechanical attribute could be found relating to vehicle action. Action could not be repeated by technician. Vehicle released to owner. No explanation could be given as to this action. Dealer did not follow up or continue investigation.

- Fresno, CA, USA

I own a 2007 Suburban that has no acceleration when merging into traffic or when passing. Potential rear collision on interstate highways. Engine tapping is moderate to severe, sounds like metal to metal impact. Have filed a complaint to GM, and was told they are aware of the problems. They offered to pay one month's truck payment as compensation for the problems. Just before parking when vehicle is in slow roll it will suddenly lunge forward. Vehicle is definitely a lemon.

- Millersville, MD, USA