vacuum advance idle issue?

Maybe the fuel is contaminated, or just plain wrong.
Along those lines, if the car has been sitting for a while, the fuel will be broken down and crappy and will tend to knock badly. Did you get all of the old gas out? If not, time to do that before you go ANY further. It will not just knock, but will varnish up the intake guides badly and cause the valves to stick/sieze (intakes in particular). That will cause bent pushrods.

Just dumping fresh fuel in with the old bad fuel will not fix this.