I have a 1984 Rx7 GS, with a 12A Carb'd. I got it from my cousin who drove it daily up till 04 when it started having problems. when i got it in 2010 after sitting for 5 years without starting, i changed the oil, drained the gas and put new in, new filter, new plugs and wires, i got it to start very easily, but it would not idle, or run with out you throttling it open and closed rapidly to keep it above about 3000 rpms, it revs up fast and normal above 3000 but under that it runs terrible. I thought the carb might be clogged so i took it off and rebuilt it, i cleaned it out and dipped it in a carb dip and blew out all the ports and lines, removed the emissions components and rats nest off the motor, the shutter valve is also removed, along with air pump, and the valve on the side of the intake that the air pump runs to. i put the carb back on, and it still wont idle, i can pump the gas like 10 times or so and get it to fire up, and run if i keep it above 3000, below 3000 it sounds like it basically shuts down, and wont start running even if you throttle it. please help me i need to get it up and on the road, thanks Dan.

sounds like you have a major vacuum leak

Nope. already checked all the little vacuum lines even the big one on the back of the intake