i agree with what Toyota Karl says, makes sense, that would explain why the car suddenly dies when you come to a stop, when you drive the car the throttle plate opening and closing controls engine speed, but when you let of the gas the throttle plate closes, it is then up to the IAC Valve to control airflow.
it is possible you have no engine codes because it is still functioning properly, there may be some excessive carbon build up in your IAC, take your intake apart and have a look down inside the throttle body and see if its really filthy, if it is get some throttle body cleaner and spray it down really good, take a old tooth brush clean it out, then take a rag and polish out the excess residue. if you can un bolt the IAC valve itself, and give it a good cleaning, and the passage for it as well and give it a good cleaning.
keep in mind if you have to un plug anything electrical to disconnect your battery, and also when you start the car if you used throttle body cleaner keep in mind it may be hard to start at first because the throttle body cleaner in the intake may make a little bit of a rich condition.