[NiftySVX]

I wouldn't try it with a variable resistor. I am skeptical that a temp unit could cause this severe of a drivability concern. I think your best option at this point is to read and analyze the scan data. A trained eye could see any of the symptoms we have suggested anywhere in this thread.

Again, it is fun to theorize about these issues, but it is not very useful. I really think you are going to have a big six problem. Breathing, fuel, maf, cam, crank, ignition (IGF, IGT).

I could be in error (not wrong, I am never wrong, except for that one time I thought I was wrong but I was mistaken and that is different)

You need some basic things for the engine to run.

1) ECU needs to know what the air is going in so it can set injector duration and etc
2) The ECU needs to know where the camshaft is at so it knows when the valves are open and when to fire the plugs
3)The ECU needs to know where the crank is so it knows where the pistons are and when to fire the plugs and run the injectors
4)The ecu needs to be able to charge and fire the coils AND in most cars the ECU needs to see the voltage from the collapse of the coil indicating the plug fired
5) you need fuel pressure and fuel that can be burned sitting behind the PWM solenoids (injectors) to go into the engine
6) you need air coming into the engine and leaving it.

You have these things and the engine will run. ECT is important for fine fuel trim but as I said this is to a lesser degree and I doubt a failed ECT sensor would cause this major of a drivability concern. In cold weather, I can see a failed ECT sensor making starting hard/impossible.

The only thing I am thinking of that could mimic these symptoms is an internal torque converter problem but that is a stretch in likelihood.