Slant 6 Vibration

Squirt water along the intake manifold gasket. That is how I found mine was leaking in my 1996 2.4L. I knew I had a vacuum leak since it idled too fast, even with the IAC port plugged shut. When I sprayed water there, the engine rpm suddenly decreased. Pulled the manifold and the gasket was hard and cracked, with chunks missing. What do they use today? Cardboard? The replacement Victor-Reinz looked like the same thin black stuff that failed.