The theory of introducing some flammable gas into the intake manifold works. We recently did exactly that and appeared to find the culprit with the soft mounts. New soft mounts and $120.00 later the loping idle and lack of a decent reading with our vacuum gauge leads me to believe the starting fluid test did not perform as intended. Not sure where to go from here, has anyone had luck with the "smoke test" for vacuum leaks in the intake system?
Yes, we are off topic