Visually inspect intake ducts and duct joints tight clamps no splits/cracks/holes
	Visually inspect all vacuum lines and connection points.  Here's a picture (for a 91, non-TCS) no loose fits no disconnected hoses no broken plastic nipples no splits/cracks/breaks check all vacuum connections turbo bypass line turbo boost gauge line feed line for both of those, from manifold PCV lines fuel pressure regulator line evaporative canister line vacuum take-off points at the manifold  check the rubber grommets for pliability and a good seal a bit of lubricant helps
	Check the turbo bypass valve Disconnect the vacuum line from the tee suck on the line no resistance = bad valve

NOTE: These are my notes from a generic fuel injection book.  I have not done all of these procedures, but they sound reasonable to me.  Corrections and updates would be appreciated.

	Perform propane-injection leak test (if nothing found visually) First, disable the Idle Speed Stabilizer by clamping the line or disconnecting the electrical connector  (this is true for '91 and later; not sure about earlier)
	Fit a piece of tubing to a propane torch Preferably, use several concentric sizes to step the diameter down to about 1/8" I.D.
	Perform the test with the engine cold so the cooling fan does not come on and disturb the air flow
	Start the engine
	Crack the valve on the propane torch to obtain a small flow of propane Direct the propane toward any suspected leaks An increase in RPM indicates a leak (Why?) Don't forget to check the intake manifold joints and fuel injector seals