Help!!! Motor dies when coming to a stop?

ok i have a 1964 plymouth valiant with a 273 and push button transmission, ok so every time i am coming to a stop the idle goes real low and will die, it has electronic ignition and it only will do it in drive, it will idle fine in nutral but in drive it just goes very low and dies but when your driving it acts fine.


the timing is where it is at stock
and the motor is all stock

some one help me i cant figure it out?