I have a 1994 Nissan Altima GLE 2.4 L and the vehicle is idling rough. ???

What is your question?

I have have had the distributor replaced and spark plugs changed about a year ago and 12,000 miles later, The distributor was replaced only a year before that the first time. I read some comments regarding a leaky intake manifold gasket as a possible problem. How do you check for a vaccuum leak?