Well, after giving up at looking for one at part stores, I finally broke down and made one. And surprisingly, it works perfectly. The only materials you need to buy are 1/16" metal cable (about 5' so you have room to work) and some 1/16" wire crimp ferrals.

Run the wire through the old cable sheath, and make a small loop at the top near the throttle body. At the bottom, all you need to do is transfer all the plastic pieces that were threaded on the old one to the new one, use crimp ferrals to hold them in place.
Once you have all that done all you need to do is hook it up. Run the cable just like the old one, but instead of attaching it on the throttle body where it is supposed to go, take off the throttle return spring and put the loop at the top over that post and then return the spring. Make sure that when it is all said and done you don't have any slack in the cable or you're going to run into idle issues.

I'm sure there are those of you out there who probably already figured this out, but for the other guys out there who are having a hard time finding the right throttle cable for your '89 IROC, this is a trick that will work surprisingly well. I don't recommend it as a perminant solution, but it will hold you until you can hunt down the right cable. If you have any questions on how to do this feel free to ask.

 

http://www.partsamerica.com/productd...pe=656&PTSet=A


I was driving around with wire attached to a wrech to adjust my throttle coming from the hood into the window. Part stores call them accelerator cables. Easy to find :P