Al,

Your problem is identical to mine, to which I have not found the solution.  But, I am a few steps closer to it than you.
I own a 91 Carat and it exhibits identical cold idle symptoms.  I have replaced the idle stablizer valve, both temperature sensors, fuel injectors, fuel pump, fuel filter, and fuel pressure regulator.  Guess what?  No help.  I have resigned myself to live with it until I find an idle speed regulator relay ($$$).  The idle speed regulator relay takes the various input signals and sends an analog signal to the idle stabilizer valve.  This analog signal tells the idle stabilizer valve to open the correct amount to produce smooth idle.  The idle speed relay is located in front of the right tail light (remove the tail light and peep forward into the gloom and you will see a box with wires going to it).  In this position this box gets heat and vibration, and after many years the wear takes its toll.
I believe that this box is my problem and yours too.  List vendors sell replacement boxes, but they are pricey.  If you opt to replace this box, let the list know of your success (or failure).  Others would like to learn from your experience.
By the way, my van idles great when ambient temperature goes below 50 degrees F.  If you have not owned your van in the winter, you may find that your problem goes away until spring.
Don't bother to replace any other fuel injection parts (unless you just want to), they are not the cause of your idle problem.
Other listees, any comments?

Dennis Lockwood
91 Carat
Original Owner