DynoMight88

I have a 1988 Rx-7 Turbo II. My issue is that when i start the car it dies out right away unless i keep reving it up, but if i stop it will die out again. when i drive it if i stop at a stop sign or red light it will die out when i stop unless i rev it up. sometimes it works great but when it does work great it idles funny it goes from 800 to close 2k then goes down to 1k then does it all over again. i no my o2 sensor is not attached and i am working on that now but i just wanted to get some advice so that is it isnt my o2 then ill have a back up plan. Can anyone help out???