I was travelling on the interstate at 75 miles per hour and the vehicle started slowing down and completely shut down. The engine warning light then came on and I had to coast to the side of the road. I was on the side of the interstate for about 45 minutes and the vehicle had to be towed. The repair shop informed me it was a complete engine failure requiring a new motor and that GM has an extended backorder time due to this being a widespread problem for these model years with the 6.2L gas engine. The vehicle is currently at the dealership and will be there for several months waiting on an engine.