Suspension Noise problems of the 2014 Chevrolet Silverado

I purchased the 2014 chevy Silverado crew cab lt texas edition from reliable Chevrolet in richardson, TX. Immediately after purchasing without a test drive it noticed that there was a vibration, steering problem, and scratches on the bed. . Because it was a demo of was told by the new car salesman that they had made sure the vehicle was inspected and that the scratches were superficial and it's a demo so that's how it is. I spoke with the business manager and they put a spay in bed liner to fix the scratche's and did a balance on the tirer. I picked the truck up and the steering and vibration problems were still there. It went back into the shop again and they couldn't duplicate any problems. The steering is almost impossible to keep in a straight line it swerves as if the truck had a few drinks. I told them it don't feel safe driving it and I'm afraid I'm going to hit someone. I will not drive in the middle lanes. I have to drive on either far left or right lanes to allow for swerving. I complained to gm. . Got excited because they sent me to another dealership and same thing happened. . Went for a test drive. . They felt something wrong but mechanics can't "duplicate" the problem. They said they test drove it again but in don't see how when the roads were iced over. I called gm again and I'm at a new dealership they test drove it with me and headed a new popping noise when the wheels is turned and felt steering and suspension issue. They kept the truck but once again not able to duplicate. I've had a few loaners and none of them drive like mine. The truck has also had problems with ac and whiny noise in engine. I'm was supposed to pick up the truck today but I complained and they were going to test drive it again. They don't factor in the time and inconvenience of having to take off work plus gas and miles in trying to get this fixed. Not happy with this truck.