help my 74' 318 wont idle

I have a 74 duster with a (probably) stock 318, last year one day it just stopped idling, the engine will run if I keep a foot on the brake and one on the gas. I dont have a tach so I don't know what rpm the engine dies at. any help is appreciated.


also the car sat for 5 to 6 years before I got it. I replaced the fuel pump, rubber fuel lines, fuel filter, oil, coolant, and I only drove it for most of one summer.

EDIT: I only got the car last year. and it was garaged over the winter.