I have had the intermittent stalling/shut down problem while driving myself, traced it to the Camshaft position sensor, All i have ever done is unplug, shoot some contact cleaner on the plug and the sensor and plug it back in. The problem goes away for around a year or so. Its not a big deal for me, it has just sort of become part of my routine maintance for the car, every 6 months or so I clean it again..
The camshaft sensor lives in a pretty hostile enviroment, its right at the front of the 3.5, near the right side timeing belt cover, so its pretty understandable why it needs this.