RX-7 wont stay running

I have an 87 rx-7 with an engine from a 91, its a 13 b cosmo, it has the lighter rotors, when I purchaced the car the previous owner added a full exhaust to it, may or may not be relevent, anyhow the problem is that after a short while of idling the car will die out, it restarts every time and can be revved right after restarting, but after a few minutes of idling it dies out again, it will drive, but ive only barely had it in 2nd gear then it dies out, if I try to rev it up it dies out even faster wether driving or idling, its idle is around 1200 and every now and then when I first start it the idle oscillates from 1200 to 1500 rpm, up and down until it is almost warm and it is revved a little bit, I did notice 4 small clear lines on the fromt left side of the engine that have air bubbles in them, the air bubbles flow with the fuel when the car is running, ive primed the system, tried to bleed it by taking the hose off the rail and cranking it, and tried unpressurizing and repressurizing it, still has bubbles, plugs looked like they had a bit of carbon buildup on them, I cleaned them up and tested them off a ground while cranking, still has good spark, just need to know what the problem most likely is so I have somewhere to start.