I have a 2005 Roadster that is doing the same thing. I already replaced the Crankshaft position sensor. Now is stall occasionally. This occurs sometimes when I am driving. It just dies. I have power because the lights and radio stay on but the engine does absolutely nothing when I turn the key. After about 5 minutes it starts up. A real pain in heavy traffic!! If you get any good answers, please send them to me as well. I would appreciate it!

Robb