Are you aware that the ThermoTime Switch only functions when the starter is engaged? It has no effect whatsoever on any running problem you are having! Perhaps the schematic below will clarify the matter ... the starter solenoid-ThermoTime Switch-Cold-Start Solenoid part of the circuit is the same as your car ...
What resistance range were you using to check the switch? From terminal 'G' to case ground is a heating element, and if your switch is really measuring zero Ohms on a 200 Ohm range, then it is indeed bad. Terminal 'W' to case ground is nomally a closed switch at room temperature ... when it opens is dependent on the markings on the switch body, and 45° C is typical. The chart below has some test values in it, but please note that the 911 Thermotime switches have round 'Faston' connectors, not those tiny 0.110" pins ... so those chart values can be used as a guide, but they aren't for the exact same switch!
