idle too high, makes undriveable

Could be a leak elsewhere, use carb cleaner to gently spray around the intake everywhere that could leak, vacuum ports, intake runner plugs, carb mating area, even intake gaskets. Anywhere air could get in is a possibility of a vacuum leak. The idle will change as you spray an area with a leak. I have done this several times with starting fluid, but that is very dangerous, one stray spark and whoosh it's on fire! Carb cleaner is no where near as volatile and therefore safer