My Grand Caravan has a tendency to stall when it hasn’t warmed up yet. It seems to only do it if the weather humid or wet. It quit doing it this fall for about two weeks when it was really dry. It has also stopped now that the temp outside is around 3 or 4 and really dry. When I start the van I have to keep my foot on the gas until the van warms up otherwise it will die. After the van warms up, it rarely ever dies.
The symptoms you describe usually point to trouble with the ignition system. Things like the plugwires arcing to ground due to the moisture and a bad connection to the plug. The trouble may also be due to a bad connection in the wiring for the engine also. Possibly the wiring to the MAF sensor or TPS sensor.