Why does my Saturn SC2 stall out periodically?

What is your question?

Sometimes my car wont start i will turn the key and you can hear it trying to turn over but it wont after 5-10 trys it will usually start. After it starts sometimes it will just automatically stall out unless i rev the gas pedal. If i am at a stop sign or a redlight it will either stall out completely or my RPM'S will drop to zero without stalling out completely. I either have to restart the car or rev the gas pedal. I have given it a complete tune-up, changed the throttle ignition sensor, oxygen sensors, coil packs, starter, altenator I have tried dry gas, injection cleaner and various sorts like that I have tried everything i have been told and am running out of options as my starter just went again after only a year of having it. I would appreciate any advice