my first DIY on my 993TT
#16
Race Director
Buy a small (i think they are 32oz) bottle of propane with a valve on it to control the flow (the torch tip helps to positively locate the flow of gas).
Open the valve a good bit and move it around the engine bay. If there is a cracked/unattached hose, when the propane gets into the hole/opening, the engine will rev up a bit. Its not foolproof but a pretty quick and dirty way of determining whats up.
Some shops have smoke machines they can hook up to the intake to identify vac leaks.