CIS idle & Vacuum woes

[zeroid at hotmail.com (Ben Channard)]

Hello list:

     1981 with CIS lambda.  Recently changed plugs, cap + rotor, injector 
O-rings, oxygen sensor.  When warm, the car won't idle.  I believe that 
timing is close to right but mixture has been empirically adjusted (i.e. 
monkeyed with) that I have no idea how far to the dark side it's gone.  Once 
warm, the car will die unless I keep my foot on the throttle.  Starting and 
running seem OK.  Sometimes the car will idle for several seconds then 
slowly die.  Is his behaviour suggestive of vacuum leaks?  Since the car 
won't idle, I can't do the propane/carb cleaner trick to track leaks.  By 
the way, the idle screw is screwed out really far.  So, should I concentrate 
on leaks or look elsewhere?

     I also have a question concerning the vacuum manifold which comes off 
the intake manifold and connects to the brake booster through a rigid 
plastic tube.  The manifold has two nipples which are easily snapped off.  
I've repaired these in the past by glopping a collar of JB Weld to hold the 
broken stub.  Can this part be replaced by a couple of T-connectors?  The 
OEM part has a widened, disk-like flared portion where it attaches to the 
tube going to the booster.  Does this contain a valve of some sort which is 
essential to proper running?  Thanks for any help.  benton-----