Over the years I've encountered numerous instances of "mystery" idling and poor performance issues that were found to be caused by a vacuum leak. Most of the leaks were not readily visible and took an inordinate amount of time to locate. A prime example would be a soft spot on the underside of the anti-afterburn hose on my 12a. Finding this leak through visual and tactile inspections were incredibly frustrating and time consuming. The obvious solution to finding these types of leaks more easily would be the use of a smoke tester. However, most of us cannot afford such expensive equipment which can run upwards of $700+. More recently, though, I found an awesome video of a homemade smoke machine. The total cost for making this smoke machine is only $15-$20 and most of the major components can be found cheaply at Harbor Freight. The components are: A tight sealing used pickle jar, a cheap soldering iron (for heating the "wick" to produce the smoke), an old cotton sock and some mineral oil, the tube and cap from a Bic pen, some clear vinyl tubing, epoxy, and a bicycle pump. You will also need a drill and a step drill bit for boring holes in the metal pickle jar lid. The following YouTube video shows how easy it is to make this awesome smoke tester:

 

That's awesome. Thanks for sharing.

 

That's great! I've wanted a smoke machine for a while now and I love DIY stuff like this so it's perfect. Thanks for sharing!

 

On my way home to make one now!