Cadillac Repair: 98 cadillac northstar stalling, spark plug wires, seville sts

Question
I have a 98 seville sts,70k miles, that only stalls in gear,when stopped at a light and only when its raining or damp out,after a couple of stalls and driving for about 25 minutes it will never stall again for the day.p1599 code comes up-undected stall-,fuel filter replaced,throttle body cleaned and replaced crankshaft position sensors ,any ideas,Thanks John

Answer
There are numerous possible faults that can cause stalling:

Moisture saturated spark plug wires until the engine heat dries them out.

EGR malfunction or heavy carbon buildup in the EGR passages.

An idle control circuit problem.

Without having access to the vehicle to perform several test procedures there are numerous other possibilities.