I would say it's a sticky shift solenoid in the trans. When your trans fluid gets dark, it will cause laquer deposits in the valve body, which in turn make the shift solenoids stick. When the car died at the stop, did it start right up in neutral/park and then die again when you put it in gear?? If so, then your torque converter lock-up solenoid (TCC solenoid) is also sticking. Basically, you need your valve body serviced (cleaned and shift solenoids replaced) , some cars you can get the side cover off with the trans in the car, some you can't, it's all about clearance.