I am the Frank to whom TnBob referred. In the process of trying to sort out the cause of the high idle, a process which involved 50+ emails, one important point has emerged: There is not one common configuration of idle air control used over the production run of the M103 engine. Consequently, all the anecdotal evidence is very likely correct, and some of that evidence will conflict with other evidence. Some of the thermistors used for coolant temperature sensing have values of many thousands of ohms, and some have values of less than 50 ohms. Some of the air valves have a no-power, rest position that is wide open, and others close when power is removed.
So, when requesting aid in solving a high idle symptom, or issuing a challenge to deliver an answer, it behooves us to also provide a full specification of the system in question; there simply is not one correct answer. TnBob did a fine job in picking his way thru a system that was not configured as either he or I expected.