How do you locate and fix a vacuum leak?
Sometime hard but if you got a good eye and a little soap and water you can spray all hoses that you see and check for bubbles also you can check with a engine starting fluid and spray a little around intake manifolds with the engine running and if the engine speed raises then you have found you leak also listen for a hissing sounds, check for cracked hoses or dry rotted hoses and so on good eye and patients also you can try with a vacuum pump but I usually find the with a little time and a little water and bubbles. Good luck hope you find it. James.
Soap and water works good. spray and look for bubble also a starting fluid works listen to engine for change in idle speed spray around common area like intake gasket and hoses that might be exposed to heat causing cracks or melting. hope that helps. easy to do with out buying expensive tools.
For safety, try a spray lubricant like WD40, if it gets on a hot exhaust manifold, it likely won't cause a flash fire! This method is also effective for finding leaks on Intake Manifolds and Carborators, but will not work on Exhaust Manifolds.