It actually just may be the old bad gas. If the fuel is that bad, the engine won't run right. I would not think that it is the fuel pump, because the engine runs. I would drain all the fuel and replace the fuel filter. It is possible that the fuel filter is clogging, but that normally results in a lack of power at high throttle openings and rpm's.
Start with getting the bad fuel out of the car.
When it dies is it mosly at idle? Or when you are coming to a stop? Or is it when you are going down the road that is dies?
Could you give me a little more info about your car. Which injection system does it have on it Port or throttle body?
In other words: Is there an injector for each cylinder. Or is there 2 injectors in the throttle body? Thanks.