2001 f150 4.6 v8 cold below 40 degrees starts then dies I have to warm up in order for it to keep running once temp is up runs fine

 

Clean or replace your IAC valve.

 

Also check to make sure the connector is plugged in firmly too.

 

Yep. The IAC valves tend to get "morning sickness" when the weather turns cooler. They build up gumminess over the summer and that stuff thickens when it gets cool enough causing the valve to stick.

Cleaning is usually a temporary measure, the problem usually returns before too long as you can't really clan all the crud out.