Mitsubishi Repair: Carburetor problem - 2.6 L Mitsubishi Engine, mikuni carburetor, chrysler new yorker

Question
Linda--

I own a 1984 Chrysler New Yorker (good shape) with a 2.6 liter Mitsubishi engine with a Mikuni carburetor. I have problems on starting on a cool or cold day.  The engine starts immediately and runs smooth for about 10 seconds. Then it runs very rich and rough until the water temp. starts to go up (the plate remains closed). Then it runs smooth but at a high rpm until water temp. is at normal operating temp. I had the choke diaphragm replaced and carb adjusted for $200.00. No change. What can be done?  I heard Chrysler issued a service bulletin and upgrade kit for this issue, but cannot find anything about it.  Thanks for any help.  

Answer
Bob: Would like to help you with this. My thought would be to get ahold of Chrysler and see what they can tell you. I would also take the car back to whoever fixed the choke diaphragm and carb adjusted, I mean $200.00 is a lot of money and maybe they did not fix it right. Could be a bad sensor that controls the choke. Do you have a repair manual for the car, that might share some insight for you. I wish I could do more for you. I did check around with a few friends that work on such years, but no one has checked back to me. I did not want you to think, I would not answer your question. Just hoped that someone would have had an idea. Hope this helps and good luck!