[AJT1961]

When it "popped" you may have blown out the round vacuum fitting on the top of your intake manifold (follow the PCV valve hose to this fitting). If that's it, all you have to do is reinsert it and lock it in place by turning it to the lock position. If not, carefully check all of the other vacuum lines and fittings, because the wildly loping idle you describe is how the engine behaves when it is sucking a large amount of air from a major vacuum leak.