Behind the big honkin' piece of plastic that is on top of the motor...

 

my 05 ram was doing the same thing wether it was cold or not i started to research it and found that it was most likely caused by the ecm valve my truck have a really low idle and got so bad that if i didnt keep it revved at around 600rpm it would just turn off it turned off on me maybe 5 times two of which were while on the freeway going 65 not exactly exiting but when i was going to go to the dealership it mysteriously judt fixed itself im thinking it was clogged and finally just worked itself loose havent had that problem for about 6 months now

 

diff lock sticking?

 

Yeah man, I assume you have a 4.6. On the Stang forums you hear it so much that even if you ask them "why is my car pulling to the right?" they'll tell you to change the IAC before they give any other input. I actually did have a problem w/ mine and replaced it on the Stang.