318 Wont idle

It runs smooth at high idle.

I just checked the timing, and it is set at 35 degrees total advance. Still does the same, when adjusting the idle screw down to bring the motor down to idle, it chokes out and dies, but give it just a touch of throttle and it revs up nicely.

One thing i noticed, and not sure if i remember wrong, but when i was checking the timing it dosnt stay put every hit, but jumps back and forth by several degrees.

When checking the timing, i checked it with the vacuum advance unplugged and capped, then set the rpms to 2500, turned the dial on my timing light to 35, and i didnt have to move the distributor hardly at all and it was at the 0 mark, though it would jump several degrees back and forth but always come back to 0. hope that makes sense.

At a loss, dont know what else to try.