I've bought a brand new Ford Mustang 2007. The car started to stall out after just a few months. I took it to the local service center 4 times, and they tell me that they cannot find anything that needs to be fixed. But obviously I have a problem. I can't drive it because it can stall out any time. Also, my engine light came on one or twice.

I don't know what to do. I regret my purchase.