When i was taking apart the old one there was a wire connected to the canister....Does that need to be connected?

The car is a 91 Camaro RS 3.1

Now the display says Check engine soon all the time

 

Plug it back in . Or your car will run like crap. Yes it has to be plugged in. Its a air/fuel sensor. After you plug it back in reset your computer in your car. Just un plug your batt for a minute or so the hook your batt back up. That should reset your computer and the SES light wont come on unless you have more then problem in your car. Then it will come back on. Take out that sensor in your canister drill a 5/8" hole in your CAI pipe and screw the sensor in that hole and plug the wire back in.

 

Yeah, your motor needs every sensor it's got... none are optional... not like the old days!