Car Stalling While Driving

A few years ago was the first time my car stalled. I was exiting the highway making a left turn when my car stalled, I was able to pull over without power steering or breaks, at this time my car restarted no problem. Now, a few years later it is happening again. I read the code and all I'm getting is p1614, the dealer says this only tells them why it won't start again, not why it is stalling while moving and they are unable to fix it. My car does not show any warning signs that this is about to happen, there is no break or skip in radio or lights, my power steering, power breaks, and accelerator are gone. Every time this has happened I have been on a straight road and able to difficultly pull over and stop but it doesn't restart. I have been told by the dealer that cars have been stalling since they've been on the road so they don't understand why I'm so upset about this - well I am, it freaks me out that I can be 40 mph and loose control of my car - now I'm at a loss of how to go about a diagnosis, I don't have endless amounts of money and I don't feel safe in my car. I don't even know where to start.