Regarding the scanner problem: Your '94 has an OBD2 connector under dash, which is why they were able to connect to it at all, but it has OBD1 programing. (the simplifed version). There are some people here on the club who have ACTRON CP9145 scanners with a special cable you can buy that adapts it to the '94-95 situation.
As to checking vacuum leaks:
First locate all the vacuum lines in your engine compartment. They are the thin hard plastic and/or metal lines that run throughout the compartment. They are a low pressure line, so the connectors are simple rubber push-in types. Follow the path of each line and make sure that none are disconnected (pulled loose). Also check to make sure that there are no small splits or cracks i the lines or (more likely) the rubber connectors.
Repairs on these are cheap and easy. Just buy the generic vacuum hose at your local parts store. It usually runs about $1.00 a foot or so.
If you don't see any obvious problems, use a can of Carb/Choke cleaner and spray it around all the lines while the car is running. If there is any change in the engine while you are spraying near a particular line, then you know where to look closer.
Throttle body cleaning has been covered here a number of times. Try a quick search on "Throttle Body Cleaning".
Also, even though you just had the battery cables changed a few months ago, it does not mean that corrosion could not have formed already or that you might have a loose connection. It doesn't hurt to check it out and costs nothing.
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