1997 Ford Crown Victoria LX stalling/quitting

My 1997 Ford Crown Victoria LX (~90K miles) is stalling and then quitting during normal city and/or highway driving. It first started 3-4 months ago (Jan-Feb) when driving on the highway... there was a sudden loss of power despite continued application of the accelerator pedal until the engine quit altogether. I was able to restart (the car's idle seemed normal) and continue my trip without further incident. Connected an OBDII code reader when I got home... no codes nor check engine light. Since, I have confined my driving to more local driving but the car still stalls/quits unexpectedly. Each time I connect the OBDII code reader (which now travels with me)... still no codes. Yesterday, the car quit 4 times within a mile or so of my home... still no codes. Each time, I can restart the car and proceed until it quits again. The stalling/quitting is becoming more pronounced. I'm thinking something related to the fuel system or the ignition system but don't know where to start looking in the absence of any OBDII codes... any ideas?