general problems of the 2010 GMC Terrain

On 10/17/2013 my wife experienced a sudden acceleration while pulling into a parking space at our local walgreen's pharmacy. As she was pulling into a parking space in front of the pharmacy the car kept moving forward slowly although she was pressing on the brake pedal as hard as she could. The car crawled up the concrete curb stop slowly and hit the steel pipe bollard placed in front of the curb stop to protect the walkway front of the store. No injuries occurred to my wife, no one was on the walkway at the time. Only damage was to the bollard (bent over) plastic bumper, grill and right front fender of the car. Bollard and a trash receptacle brought the car to a stop. This is the second time this occurred. The first occasion was about a year ago when I was driving on a neighborhood residential street approaching a stop sign. As the car was slowing down and I was pressing on the brake pedal the car kept moving forward with the brakes being fully applied. Could hear the engine straining at an increased rpm. I lifted my foot off the brake pedal and jammed it down hard again and the car came to a stop at the stop sign with the engine in normal idle. In the three years we have owned this car these are the only occasions the problem has occurred.