I don't know what's wrong with my 06 4.8is. Last Wednesday while driving home in the rain my X5 began surging and running rough. When I stopped at a traffic light it stalled and would not restart. I had it towed to my local BMW mechanic and he has not been able to find out what's wrong with it, he says that the computer is not throwing any codes. He mentioned that it might be a problem with the air intake system. He said that I might need to have it towed to the dealership. Does anybody have an idea of what may be wrong? It is out of warranty and I need to get it fixed.