HELP!...problem with my 01 Stang

[2HOTT4U]

Hi everyone.......I have a 2001 Mustang V6 and for some reason when it gets cold out at night, sometimes my car does not want to idle. I can turn the key, but it won't idle, so it wont start...I had it towed to the dealer back in december and they didnt look at it till 2 days later because of xmas and they said it started right away and they couldnt find anything wrong with it. So i said ok whatever maybe it wont happen again. Well it did about 2 months later.....I tried to start it and it didnt want to idle, so I had my dad look at it and in order to get it started he had to step on the gas while he turned the key to keep it idle and then it was fine like nothing was wrong with it, and it started with no problem later on that day. Does anyone have any idea what could be wrong? Well it hasnt been cold for awhile but im afraid it will happen to me again when winter rolls around and my car already has 27,000 miles on it so the warranty will be up soon....can anyone help????

Thanks!
Jackie