truck randomly stalls out, but runs perfect otherwise.

[yellow400ex05]

Alright I recently installed a new Quickfuel 780cfm carb on my truck that has a BBC. electric choke vacuum secondaries. today while driving it in 20 degree weather it warmed up fine drove down the road okay but it would stumble at low throttle. as if it was trying to stall for a split second, but it accelerates fine pulls hard plenty of fuel, idles nice. timing is good all was fine a couple days ago.

now when i have it in gear or idling is when it will stall, and it doesn't spit and sputter then dies, it just dies, as if you shut the key off. to start it back up it'll just crank unless i put the pedal to the floor. would this be choke related maybe?

i checked the choke and its not sticking on, or anything.

could a bad ignition switch cause this?

the truck turns over every time though. starts right up, unless you try it right after it stalls out, then you obviously have to hold the gas pedal down..