How to test for a vacuum leak?

[Ciara99]

am trying to check my car for a vac leak. 89 mustang 2.3L. I dont hear anything obvious. What kind of equipment do I need and where do I get it. Also how do I run the test. Thanks

 

[wlabrum]

the easiest way to check.......well may be the safest is using soapy water
spray in areas of concern idle should stabilize as mixture temporaly closes off vacuum leak

i use carb cleaner BUT ITS DANGEROUS i have caught more than one car on fire

 

[mg man]

The way I check for boost leaks can be used for vacuum. Hook item in picture to throttle body and pressurize to LESS than 10psi and can hear or feel the leak. Minus the black metal pipe.
http://i177.photobucket.com/albums/w224/mgman75/100_5699.jpg

 

[Red_LX]

Vacuum leaks are very difficult to find on newer cars. About the only thing you can do is go over everything very carefully and see if anything is obviously disconnected or cut.