So this is my 5th thirdgen but the first one I have decided to keep fuel injected. It's a 1989 GTA with the L98. I've had some idling issues lately and got a code 33 so naturally I checked the TPS, IAC, relays, etc... After taking the TB off I realized the whole plenum, runners, and TB needed a good cleaning. In the rear this piece is connected to the same bracket as the coil and vacuum lines from the EGR and TB are connected to the top of this piece. When I pulled it out I found that it was not connected to the wiring harness at all. So my question is if this was not connected could this have been an issue with idling? Also, it appears as if there should be another vacuum line connected to the rear of it next to the connector, or is that just to expel excess air or what? Thanks all!

 

I'm not sure what the Code 33 is, but the component your holding is the EGR valve solenoid. That single port you see in the first photo is a vent, no vacuum line there. There should be two vacuum connections at the other end of the solenoid.

 

It's the egr control solenoid gets ported vacuum from under the throttlebody.

http://www.chevythunder.com/maf_code_33.htm