? on emissions 5Ktq passing NY state Inspection

[Sonar465@aol.com]

This morning I went to get my '87 5Ktq (115K miles, IA Stage II) Well it did
not pass the first time.The car was warmed up but bot the Hydro Carbon's and
the CO2 were a bit on the high side, not alot but more than was acceptable in
NY state.  The machanic then disconnected the O2 sensor and the emmisions went
down like crazy.  My question is why disconnecting the o2 sensor did the
emisions go down.  I did notice that one of the large diameter vacum hoses
(runs behind the head) is collapsed and there is a hole in it.  I have ordered
a new hose but I was wondering if anyone could shed light on what the O2
sensor is doing to increase the emissions?

Cheers,
Jim