My car sat with in idle for over an hour with AC on. When I went to drive the engine shut off when I hit brake. The gas pedal must be pressed to start. If you take foot off gas or press break the car shuts off. I checked vacuum lines for leaks and found none. What could the problem be. Thanks is advance.

 

Welcome to DF
Have you tried to see how the engine runs with the A/C off? To me it sounds like the idle is too low.