Horrible running 8v

[nefarious at drumatix.net (Jason Peters)]

Hello everybody,

  I'm pretty new to the 'rocco list so excuse me if this is an easy
question/fix.  First a little background:
'83 'rocco
8v on CIS

Okay, so the PO disconnected the O2 sensor because the car wouldn't run
properly with it connected.  So I assumed it was a bad O2 sensor.  I know I
should never assume anything with these cars and I should have guessed that
a faulty O2 sensor would be too easy.  Anyway, I replaced the O2 sensor with
a nice new one, connected it and fired it up.  Seemed to run fine for the
first few minutes(maybe till the sensor warmed up) after that the idle
started to hunt around up and down.  Backed out of the drive way and the car
would barely go.  It sputtered and stumbled almost to the point of stalling.
Nursed it back to the driveway, unplugged the sensore and it started running
fine again although the idle does seem high (1100rpms).  I'm a complete CIS
noobie so any and all help is appreciated.

Thanks,
Jason