Strange Cold-start Behavior / '83 258 with Feedback BBD

[markindy]

I'm trying to sort some cold-start issues.  When I bought the car it ran fine, but loped at hot idle and the electric choke didn't seem to function at all.  The original carb's barrels were carbon-black and the wire to the choke had been soldered-on.  I bought a cheap Chinese replacement carb as a stop-gap, and a rebuild kit for the Carter. 
The knock-off carb actually works great when the engine is warm, but cold-starts are still strange.  The electric choke and vacuum dashpot seem to work as they should, and the car starts wonderfully for about 1-2 seconds then shakes badly...like it's running on half the cylinders...but will smooth-out after a minute or two.  The connector for the feedback solenoid seemed flimsy, so I installed the original solenoid onto the new carb...but no change.  I'm not sure the feedback system has anything to do with this problem, but thought it was worth a try.  Again...once warm, everything is great.
Since the air-pulse system is useless due to rusted-off connections, I'm thinking about ditching most of the vacuum nonsense and going with a Carter that doesn't have a feedback solenoid.  This would at least preserve the PCV and EGR systems and make me only a mild eco-terrorist.  Anyone have other suggestions or things I should check?

[89 MJ]

I think its worth rebuilding the original carb and see if that fixes it. It seems like with these cheap, Chinese knockoff carbs you either get a good one or a bad one out of the box and no amount of adjusting will fix it.
I suppose you could check for vacuum leaks using a can of brake clean around the base of the carb, but that's all I would try.