Intake manifold on 1994 GMC Yukon

What are some of the best ways to test for a leaking intake manifold gasket. I have a miss during highway accerating. Thanks

Asked by for the 1994 GMC Yukon
Spray 2+2 around the intake manifold to see if the RPM's (idle) increase or decrease. If it makes a difference in the RPM's, you probably have a vacuum leak.