My truck will not stay idling.

[geezer#99]

Originally Posted by 1964_C10

The carb is a rochester Quadrajet 4bbl one of the choke plates is closed and one is open.

THere's only one choke plate. It's the front one. THe back one is the secondary air door. It's supposed to stay shut until needed.
You likely have no working choke, that's why you need to hold the throttle open to keep it running.
Take some pics for us.
We might see what your choke problem is.