I just got done driving like 900 miles today and when I stop my car seems like it wants to die,, it usually idles at 800-1000rpm and it kept dipping down and wanting to cut off and then it would catch it self. What could be the problem?
Please learn to use the search function - most basic issues, in one way or another, have been discussed at least once.
But I want to welcome you and not scare ya off, so today gets you a freebie. It's likely your IAC (Idle Air Control). You can clean it by spraying it with brake cleaner, but on a 5 year old Stang, it may have seen it's better days...it's fairly cheap, last I recall.
As stated, do a seach of this forum for "idle die iac" and you'll find more details.
And again, WELCOME to StangNet!!!