Truck will start but will idle down and die
I have a 1975 F100 Ranger XLT Supercab. It has a 302 with 2 barrel carburetor on it. I just rebuilt the carb and replaced the mechanical fuel pump and bypassed the electric fuel pump some guy had on it. Fuel filter is clean. I can turn it over no problem, but it will run for about 3 seconds and will idle down and die. If I hit the gas pedal it will run but will again try to die when I let off. I can not see any vacuum leaks. Any ideas?