Ok, I recorded a video to help show what my car is doing. Here is some background information. Its a 86 Trans Am with a 400ci small block with a 86 tpi setup on it. The car was originally a LG4 motor. Anyways, what it does is that when i have the scanner connected and i am reading the data from it the idle seems to be fine and it doesnt need me to give it any help keeping it running. But as soon as i unplug the scanner it drops rpms and will die unless i give it gas. Then once i plug the scanner back in and go back to reading the codes it will idle fine again. The only code it is giving is #39(i think?) its the one that is MAF burnoff. It also seems to be going in and out of open and closed loop. I tryed to show all of this in the video. Heres a link to it on photobucket. http://s975.photobucket.com/albums/a...t=IMG_0378.mp4

 

I had a similar problem with my idle. Either it would die or idle at 4000 RPM. I tried to get it fixed by 3 different mechanics without success. Most mechanics don't know how to work on these old cars. While waiting in line for the smog check it died again and was hard to restart. I had the smog guy look at it and he fixed it perfectly. Best $200 I spent.
It is probably your smog crap that is causing the problem. Have a smog guy look at it.

 

I dont have most of the smog stuff on it. It has the EGR still with the little solenoid next to the distributer. But i dont have the fuel vapor canister, or the A.I.R. stuff.