RE 2001 Ford Explorer It has a new battery, coil, and wires in place. The truck will not start below -7 F despite strong cranking; in these temperatures, sound of fuel pump priming is muted or absent. Upon rewarming, the truck starts briskly and pump sounds return. No other classic signs of fuel pump failure. Any ideas that you may have would be hugely appreciated. Thank you!
I have experience on similar situation. It was -20 degree Celsius and engine was choked on my case.
As people indicated your problem could be the fuel pump. Trapped water (ice) inside the gas tank can cause failure of the pump. You may need to check if fuel pressure is ok on the engine side.