My 97 4.6 auto always starts easy with
just the turn of the key. However,
with the temperature down to -3 degrees
I turn the key and it cranks and a loud
whirring noise starts up. The car will
catch but not remain running without
goosing the gas.
I guess the whirring is noticeable because the
truck is not running and the dB level is down.

Any idea what the whirring is?

 

Might be the power steering pump, my 05 will do that on a real cold morning (below 32) until the fluid gets circulated a bit. If it's the original fluid it wouldn't hurt to drain it out and put some fresh fluid back in.

Cold weather also like to bring out sticking IAC's....this might be giving you your stalling problem. You can remove it and look inside the hole to see if there are scoring marks running along the shaft....perhaps Jbrew has a pic?