I've been having a similar problem as you, except mine stalls out much more often
. It's gotten to the point that I don't drive it as much anymore. Hopefully I'll have the chance in the next few weeks to do some more diagnosis. Here's what I'm planning to do, I'll let you know if any of these things work. Other than a normal tune up (plugs/wires/cap/rotor/O2 sensor/oil change/whatever)...
1) Replace the emissions valves on the right hand side of the engine. I know one is bad, and that can cause junk to get back into the carburetor, and create stalling.
2) If that doesn't work, I'm gonna replace the ignition module, but I think that when the module dies, it just goes alltogether. At least that's what happened last time mine went.
3) Replace the carburetor - since you already did this step, you can probably skip it. I'm not too keen on replacing mine, because sometimes my Jeep idles just fine, perfectly smooth.
4) Replace the Cat - might be a little higher on the list, but I'm going in for emissions testing in two months, and don't really want to replace the cat unless I know it's bad.
5) Pull my hair out 'cause I can't think of anything else that'll make the thing stall every time I stop/turn/look at it.
Good luck, and if I figure it out on mine, I'll pass the info along to you. Hopefully it'll be the same issue.
Oh yeah, one other thing. If it only happens when it's real cold out, there's a tube coming off the air intake that's supposed to pull hot air from around the exhaust manifold. You might want to check to see if it's working properly, or even missing altogether. There's a door in the air intake that regulates temperature inside the air filter box, so the carburetor sees a constant temperature no matter what the temperature outside, more or less. The door is worked by engine vacuum and a switch inside the air filter housing.