Popular Mechanics’s automotive experts outline the tools and techniques proven to smoke out even the toughest to find vacuum ...

A hole in the diaphragm allows the booster to draw air into the ... problem is a vacuum leak, you might hear a whistling sound or feel a stumbling sensation when you brake, he says.

If leaks develop in hoses or engine parts downstream from the air intake, that means additional ... throttle body evaporative emissions system, power brake booster, and several other places ...