Checking for Vacuum leaks.....

you can check you engine vac at the vacuum tree (drivers side firewall). you should have 16- 20" on a healthy motor. make sure all the lines on the tree are hooked up and not cracked, etc.

you may have to just do a visual inspection on the hoses. two methods i know of for testing lines: spray carb cleaner on the lines; when the idle changes, you have found a leak. never works for me.
other way is to use propane around the lines. same result when you hit an open line.
never done that.
be careful with them both. possible fire/explosion hazzard.

on my 88, it had a bunch of crappy lookin lines under the plenum (upper intake manifold).

for checking the EGR, with it idling, pull the vac line to it. the valve should be closed at idle, so the car should idle the same. now take a vac line off of something else (but not something important that would affect the engine's performance). hook this line up to the EGR. the idle should turn to poo, since you are now introducing exhaust gas into the intake.
good luck.