It'* hard to say, since what you describe sounds a bit more like an electrical anomoly. It is certainly something that you need to do to bring your car into good maintenance, but, you still need to check those battery cables again and follow up with us in case you have an ICM problem.
Let'* just say that sometimes, after a car has just so many miles and years on it, it needs some tender lovin' care. Call it maintenance and you'll be right.
It sounds like your vacuum lines need replacing, but you likely still have other worn out items to address before it gets back in fine fettle.
Mike: 1997 SE w/ 183K, aka White Horse
, Gutted Airbox w/K&N, drilled 180* t-stat, tint all around, clear corners w/SilverStars, "PONTIAC" light up tail, PEMs, NGK TR55s