I have a 2005 Grand Prix that is intermittently stalling. This is occurring when I am driving at 110 km and even when I am stopped at a traffic light. The engine just cuts out and I lose power steering. Radio/CD player/AC and lights all stay on. If I am at high speed, shift into neutral and then turn the engine over it will not turnover. However, when I have stalled at a slower speed it will sometimes turnover in neutral. The dealer cannot find the cause. They have taken it on several test rides and it does not stall on them which is frustrating. Now they are going to replace the ignition switch assembly. Does anyone of any thoughts on this? I enjoy the car but it is now become unreliable and obviously unsafe. Thanks!