How do you locate vacuum leaks on an engine?
The easiest way to find a vacuum leak involves using any brand/type of carburetor cleaner or any some other type of cleaner in a spray can or spray bottle. With the engine running you spray around the suspected area . If there is a leak at the location you are spraying the carb cleaner, you will immediately notice an increase in the RPM of the engine. You can use this method to find cracks in a vacuum hose that are very hard to see if they are surrounded by wiring harness' and other items. This also works if you have a carb or throttle body base gasket leaking, intake manifold gasket leaking or even mismatched manifold with the cylinder heads.