Diagram location of vacuum lines

First you have to ask how they determined that. If you can hear the hiss from a leak, you can follow the sound to the source. Next is a visual inspection of the hoses. They are shown on a vacuum hose routing diagram on the emissions sticker under the hood. There is no special equipment needed for finding vacuum leaks. The most common symptom of a vacuum leak is increased engine idle speed without a corresponding increase in power. A trick to finding that is to spray water over the engine while it's running but still cold. Watch for where the water gets sucked in and / or the idle speed slows down momentarily.

The final test does require special equipment and is for very small, hard-to-find leaks. We use this mainly in the vapor recovery system where there are no other symptoms other than the check engine light is on and the fault code relates to a small leak in that system. That is a smoke machine. It allows you to inject a white, non-toxic smoke, under two pounds of pressure, into the system. You watch for where he smoke sneaks out. Without that machine small leaks in the vapor recovery system are practically impossible to find