Seems I read about 20 years ago you could just sub a resistor (value??) to ground for the "run" (warm??) value on a switch and use it like a "choke". Off for start and on for run!!
Yes, the temp sensor is in a poor location. The valve cover will never ever get up to temperature in the winter. So, the ECU was always on 'choke' so to speak, pouring in too much fuel, in the winter.
Some people paralleled a switched in resistor, to fool the thermistor into think the motor was hot.
I have to wonder if mounting the thermistor under a valve cover bolt wouldn't help a lot.
About like this:
