I found a resistor soldered in-line on one of the wires running to the group of sensors on the thermostat housing. I had been searching for a poor connection possibly causing my car's rough idle, and found that the idle slightly surged when I moved one of the temperature sensor wires. I removed the electricalc tape and found a resistor soldered in-line with the wire. Does anyone know what this resistor is for and how significant it is to the performance of the car's idle? Any advice much appreciated.