I'd like to hook up a vacuum gauge to the intake manifold of a 1997 chevy 3/4 ton 4-wheel drive pickup with a 5.7 L engine but it doesn't seem to have any port through which to do this. It is a two-piece manifold, the upper portion being plastic on top of which is the throttle barrel and fuel injection. How is this done these days?
The last time I did any vacuum testing it was 20 years ago and on a Datsun with a simple carburator.