Absolutely check for vacuum leaks. The Cold Start Valve supplies the fuel for starting and is controlled by the Thermo-Time Swiitch. The Auxillary Air Valve supplies air and should remain open until its' internal heating element closes it. The ignition wires or cap and rotor may be having frozen condensation that reduce spark intensity. The coil should be getting full battery voltage at its' plus terminal when cranking. I would start with these items. You may want to check that there even is spark as the ignition module may have a temperature related problem.