Dart dies after running awhile

Ok, I am not too sure when I will get a chance to work on it. But I do appreciate all the replys. The Dart doesn't get driven much. And it is hard to get started after sitting for awhile. I checked it for spark one time and it seemed to be weak, But it started after some time. I don't think it is vapor looking, but who knows. It is also hard to start If I drive it and then shut it off for a few minutes. ................I am hoping to get a little time this week end to work on it. Have another dist to try out, will do that first and see how it acts. Will keep you posted.........