Engine Exhaust System problems of the 2007 GMC Sierra

The truck after 40 miles started screeching from the front when going around corners,and was reported to the dealer sam swope, I was informed that it was normal, on the way to town the truck stalled and was towed for repair turns out the coil plug shorted out wires were replaced, next day the truck stalled again towed again turns out that booth catalytic converters were plugged,booth replaced. Entering the freeway when accelerated the truck did not respond, I was informed by the dealer that nothing wrong with the tranny, now I have a clunking noise from the rear of the truck they claim not to be able to duplicate the problem, tires worn out at 27,000 miles turns out alignment problem but no cause for the squealing tires sense first reported the first day of owner ship. Same problem all the time steering wheel never been aligned anti-lock brakes never work right always locking up on breaking first thing in the mornings and the dealership not able to reproduce the problem. This truck is dangerous to drive with to any failures.