After 60-70 miles driven at 65-70mph the steering wheel will jerk to right or left. Seems like there is a sticking point and when extra pressure is applied to steering wheel to get past the sticking point the wheel jerks in the direction you are attempting to turn. Then, when you attempt to return to mid-point you go through the sticking point again and the wheel jerks to the left. Had car to two dealerships. Cannot duplicate problem. Their answer: Test drove - OK.

Called GM customer service. I was told that the problem could not be duplicated therefore it can't be fixed. There is nothing that can be done. Right now the problem is a pain in the A$$. My fear is that the wheel will jerk at a time that will cause me to get into an accident. Also; the problem seems to be more pronounced as the temperature drops.

Update from Apr 6, 2015: Dealer reprogrammed steering module. Took less than one hour. Car steers like a dream.