I've been researching the failure to start / fire , 4.3 Litre V6 Chevy / GMC engines when outdoor temperature drops. ( Weather somewhat below freezing. )
Most posts say it is probably due to a lack of fuel pressure during starting. Could be aging fuel filter, fuel pump, or fuel pressure regulator. I'm having that issue, my 4.3 L Astro van won't start. I'm gonna try the filter first as it's the cheapest fix. Can also borrow / rent fuel pressure gauge to check that. Partsource rents many tools for refundable deposit only = free .
2ndly sites way it can be a slightly weak battery or coil, so the ignition is consequently underpowered upon starting. ?