Why does my car die when it idles

This car has had a gas smell problem for a few months, that no one could find. I am beginning to believe that this is the fuel pressure regulator, if you pull the vacuum hose off, you can smell gas. But I don't know if this could have degenerated into the current problem. The car will run fine on the highway and even in town, until you stop, when it will die immediately. You can keep the rpms up over 1000 and keep it from dying, but if it falls below that it is dead. It will start right back up. It will idle (roughly) during warm up in neutral, but as the rpms come down it will die eventually. And it dies as soon as you put it into gear if you are not keeping the rpms up over 1000-1500. Thanks