Won't start in cold weather

My 1997 chevy s10 4.3 liter automatic transmission has 100,000 miles. It will not start when it is cold outside. It will start easily when the temperature is thirty or more but will not start at all when it is 10 to 15 degrees out. When the engine is still cold, during the first two miles of driving the truck will die and then start itself again without me turning the ignition. I have replace the fuel pump and ignition switch. It has not helped. None of these problems occurred during warm weather.