I am missing the plastic pieces under the car that force the air up into the engine bay. I have no idea what they are called. If you know the term for them i would appreciate it. Also an idea on where to get it. Thanks

 

Air dam

 

I found the front end 3 piece thanks. What about the 2 that are on the sides? are they caled the same thing?

 

GM calls it a Deflector, was $29.66 for the 3 peice unit when they still had it.
Part # 12395557

 

I'd been on a hunt for those myself for a bit - that is if you are referring to the two flattened pieces that raise up on the end near the wheelwell and the ends of the air dam mount onto that sort of box in the fender/front cover/etc...

I believe that they are molded in as part of the front gfx piece on cars that came with them. On cars that didn't (like mine) the dealer informed me over the phone that the correct part name is also "air deflector" as opposed to the long 3-pc "air dam" that is commonly mis-labeled with the same name.

I had a non-gfx car so I needed some that my search ended today with a call that a pair were found in a warehouse out in Nebraska somewhere and are now on their way to me new in the box....

Not sure if this was for your GTA or if you had another car you were working on, BUT, if you have a non-ground effect car, RCAR7395 had seen a set in one of his local yards.... correct for the 85-90 styled nose. I was about to have him grab em for me but then I got the surprise call from the dealer this mornin. You could send him a pm...