1) How long has it been since the car was last run. If more than a year, there may be cause to suspect some clogging in the small orifices of the injection system.
2) Does the engine stall immediately after releasing the key from the "start" position and returning it to the "run" position, or, does the engine run for a couple of seconds after the key is released from "start"?
If there is an immediate stall, the cause may be ignition related. There may be a faulty resistor in the primary circuit, or there may be a defective key switch.
If there is a short period of running, the problem is likely in the injection. Having an ignition fault while trying to find an injection problem is likely to make you feel like Sisyphus.