setting CIS mixture
 

Does anybody know if the O2 sensor should be connected or disconnected when setting air/fuel mixture?

81'SC

Connected. There is a test plug under the black plastic fuse/relay panel cover. It's round with three leads. Brown is ground. I think the one you want is green with white stripe.

Hook a dwell meter to the green and white terminal - ground the other lead. When fully warmed, the dwell meter, on the 4-cylinder setting, should oscillate around 45. down to forty, up to fifty, centering on 45. I believe big numbers mean a leaner mixture. the spec is 45 and that's probably where it will run best, too. Let me know if you need more. What you're looking at is the "oxygen sensor duty cycle."

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'83 SC

HI, you must unplug the o2 sensor in the eng compartment (left side , forward end by #3 cyl.)set your co% and plug it back in.
the round connector described by the other gentleman is the idle stabelizer bypass found in later cars. if you need to use it you will see three round holes in it. a, b, c . jump a wire from b to c, when done with adjustments, remove wire.
good luck