I just took my mustang for a drive and on the Hwy, i punched it and took her up to about 120. I then came up to a stop light and it idled up and down for a couple seconds before stalling. Why?????
Later, when at a full stop, it idle up and down. Kinda like someone was give it gas then letting off.

 

First clean your IAC. Your TPS may be messed up as well.

 

what is IAC? if this anything to do with the A/C, the A/C has been removed. It only bogs out ocassionally, like when I gunnit and then come to a stop. It doesnt do it much.

 

No, IAC is your idle air control unit. It isbolted ontothe side of the throttle body. Just unbolt it and clean all the gunk out with some brake clean and see it that helps