While doing a boost leak test I noticed the system would not pressurize past 5 psi. Does this mean that my head gasket is bad and/or leaking somewhere? And the only way to find out would be doing a cylinder leak down test?
If your intake hose is still attached to the throttle body, you need to disconnect it and plug it. Testing with the throttle attached, will allow boost to enter the
manifold and find its way to a cylinder via an open intake valve, or through the intake & out the exhaust if that cylinder happens to be on valve overlap.
Boost leak testing is usually only done between the turbo OUT and the hose that attaches to the throttle body.