The engine started to shake violently while traveling down the interstate, my speeds reduced against my will. My safety and the safety of others was jeopardized while I’m traveling down an interstate with a minimum speed of 70 mph and my truck speed reduced to 35 mph or less. After an inspection from the dealership, I assumed the responsibility of having the engine rebuilt that cost me thousands of dollars. As the vehicle started to reduce speed is when the onstar alert went off. After having my vehicle for 10 ten days I receive it in worst condition that I gave it to them. Approximately 2 weeks later, the vehicle had to be towed to the dealership which they diagnosed it as needing the throttle body replaced. I allowed the dealership to fix that issue. Upon them returning the vehicle to me, I now have an electrical issue. The dealership stated that they may have crossed wires. The windows would roll down once I locked the vehicle, the door would constantly unlocked while I’m driving and the radio would shut down and restart while driving. The dealership was unable to find the problem so they decided to turn off everything so these I would not have these issues. Now I can smell something burning from time to time while I’m driving.