Chevrolet Repair: Truck wont start when its -5 to 0 degrees C, coolant temp, engine coolant

Question
I have a 99 Silverado 4.8 V8

When the temperature gets just below freezing 0 to -5c it just doesn't want to start.  It turns over fine and cranks away.

Once the temperature drops it starts like a gem.

I was thinking it could be the Coolant Temp Sensor but I don't have any reference values to test the sensor with.

If I unplug the sensor it starts for about a second then shuts off.  I can get it running about 3-4 seconds if I give it a bit of trottle.  When I plug in the CTS again it doesnt start.

Answer
ECT sensor is a 2 wire themistor.  As engine coolant temp increases thermistor resistance and signal voltage decreases. Pcm dual circuit improves ECT accuracy over all temp ranges.  It is located in the front of left cylinder head.

9500ohms at 32f
3700ohms at 68f
450ohms at 158f
250ohms at 194f


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