i have a 99 gt with the 5-speed, when slowing down from 100+ mph (i know i shouldn't be going this fast, but the other day my friend and i were wondering what it was actually capable of, plus i live in the middle of know where with smooth roads) but any ways back to my problem, when slowing down from that speed my car stalls. i checked my fuel pump shut off switch, thats not it, is it a safty device, or what?

 

IAC check your IAC
Idle
Air
Controller


and its nowhere not Know where

mine did that and since its under warranty off to ford i went and they replaced it but never at that speed.