Dart dies after running awhile

It just start to die, and then does. Takes about 2 t0 3 minutes, Sometime if I give it more gas it will stay running, but not always. Kindof reminds me when I had my 68 Charger. It did something just like it, and as you I thought fuel problem, turned out to be the condesor. That's why I am thinking in lines of the dist.