Brake Vacuum Leak?

[SDZR-1]

I think that I have a vacuum leak in my braking system somehow. The pedal is very hard and the car does not brake well at all (not that it was ever great). While the car is idling the rpms raise a couple hundred revs....which led me to believe that there was a vacuum issue. I am wondering if someone has had a similar experience and could point me in the right direction to solve my problem....where do I start searching? Thanks

[SharkPilot]

I've seen this before. It wasn't a Corvette but the same principal applies to any vacuum brake booster. Try pinching the brake booster hose that leads to the plenum shut with a pair of pliers. The hose supplies vacuum to the brake booster. If there is a leak in there, pinching the hose will have instant and repeatable results.

Hope this helps.
SharkPilot