Chasing Vacuum Leaks

[l.leung at juno.com]

Patient (as I'm not...anymore) '89 200Q - Chipped 1.8 Bar

Symptoms - hissing under boost, max boost about 1.3 bar definitely  leaking=
 boost SOMEWHERE. Car cuts off power if boost demands get higher
than moderate (not gentle) acceleration. RPM not dependent. Didn't have tim=
e to recheck using the dipstick test, but it did fail prior to my temporary=
 patch.

Probable cause - leak. In the time availible, I've checked all of the vacuu=
m hoses, MM hose, ISV hoses manually. Rechecked valve cover gasket. Did fin=
d one hole in the "T" breather hose on top of the valve cover, fixed a temp=
orary patch with rubber tubing and a hose clamp. (part will be ordered toda=
y). SO, it's down to the lower IC to Turbo hose (yeeesh, $$$) or the IC its=
elf. Or it COULD be the boot over the airflow plate, but that is new as of =
last year.

Question 1 - how do you check the IC for leaks?

Question 2 - where are good sources for lower IC hoses?

Question 3 - could a torn WG diaphram cause any of these symptoms (I don't =
believe it could, as it's not in the intake stream, right?)

Question 4 - HOW or more precisely, WHERE does one hook up a MityVac to hop=
efully cause enough vacuum to cause enought noise so that I can find this s=
tinking leak?

TIA!

LL - NY