A vacuum leak is an opening in the intake manifold or other vacuum-operated component that allows unmetered air to enter the engine. This can cause a variety of problems, including:
- Rough idle
- Stalling
- Reduced power
- Increased fuel consumption
- Emissions problems
Checking for a vacuum leak is a relatively simple process that can be done with a few basic tools. The most common method is to use a smoke machine. A smoke machine generates a harmless smoke that is introduced into the intake manifold. Any leaks will allow the smoke to escape, which can then be seen with a flashlight.