[dryflys]

This car had trouble with the fan running whenever the key was on. I fixed it with a fan thermostat kit and it was starting to clean out the gunk and run pretty good considering it has been running cold for goodness knows how long. Anyway, the other morning, it started and went through its usual routine. start, run 30 seconds, die, start, run a minute or two, die, then run fine. on the second die, i tried to restart and it coughed once and then was dead. cranks fine. I checked the timing belt, it is intact. I checked the computer and it reads codes 83 and 84 (on and not running) the code section of the lame manual I have sayd EGR control system. The guy at autozone said Idle air control Valve. (IACV) I have bought an IACV (because it was cheaper than the EGR valve and they had it in stock. So far no luck. I am planning on trying again tonight.
My question is this. Just what components does the EGR control circuit consist of? and Does anybody have a clue what this could be?

[90Mustang2.3]

sounds like maybe a vacuum leak to me ...

[mg man 75]

Egr is on upper intake has tube to exhaust manifold. Sounds like maybe it is leaking thru. You could try for a test. Cut piece of metal and put between egr and upper intake and see if ok then. Then decide whether to replace or ??