Well guys, here's a little background.
I had tried to test for codes by jumping the wires on the test ports a while back. To sum it up, I was positive I was doing it correctly (found 3 or 4 sources saying the same thing) and I couldn't get it to work. This is when I started to suspect some wiring issues.
Yesterday I finished my block-off plate for the egr, and installed it. I've heard mixed results, but as far as I know, if you totally unplug the egr, it should throw a cel. I didn't get one. (I still rigged up the plunger half-in deal) Not only that, but my car did go through an erradic idle a few weeks ago and it stalled, in any other car I've driven a cel usually gets thrown when the car stalls. (indicating that something had gone wrong to cause it to stall) Still nothing. I have this feeling that something is wrong, and I'm hoping you guys can shine some light on it.
What gets me, is that the light shines when I turn my key on (with all the other lights), then shuts off, so I know the bulb works.
Is there anything I can unplug that would certainly give me a cel, so I can test my sinking suspicion?
Has anyone had similar issues, what do you guys think is going on?

 

DUDE, Im not sure but maybe this will help....Let me know. CLICK ON PICS TO ENLARGE

http://www.muscularmustangs.com/test1.php

 

The reason why the CEL is not working for you to acces the codes is 87 Mustang Vert , CEL indicators were connected to the EEC-IV starting in 1988. In your case, you have to use either the VOM, or test light method to access the system for codes. The CEL is not connected to the EEC-IV in '86-'87 models. My 2¢.