The vacuum system? Just buy a can of carb cleaner, have the engine held around 2500 RPM, and spray the hoses, intake manifold gasket and throttle body gasket a little at a time, listening for a change in RPM [~500 RPM]either up or down very suddenly.
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-Harry
AIM: NDcissive
CRX and Pre '92 Civic, Engine Tech and Tuning, & Track and Autocross Forum Mod