Another problem

When I find myself sitting at a long traffic light with the car running, the idle gradually slows down and after a long enough period of time the care will die. Crank it over, and it starts and will do the same thing. It takes about 2 minutes to gradually slow down enough to stall. If I just keep tapping the throttle every 15 seconds or so I can keep it going till the light changes. It runs great all other times. It has a 318 +.040 with a edelbrock 1406 4bbl and an rv cam and a 4 speed. Fuel line problem? Carb issue? Should I just turn up the idle? Also, If I get on it for more than 10 seconds at full throttle, it bogs and I have to lift.
Any ideas as to the problem?
Dan