Engine does not want to stay running in cold weather.

What is your question?

My 2000 Toyota Avalon does not like to stay started in cold weather. I recall this happening with a previous 2000 Avalon that I owned. I was told by a tow truck driver, that all I needed to do is keep my foot on the accelerator for about 5 minutes to warm it up and it will be fine. This seems to work. As I recall, I had to have the Idle Air Control Valve replaced or cleaned or something, and then everything was fine. Is this a difficult repair?