The control of vents on the Third Generation Camaro's is done with vaccum rather than via cable or electrical means. The problem is being caused by a vaccum leak either at the control unit or somewhere along the vaccum source line. Best check for leaks on both side of the firewall. Also, the control unit may need to be replaced.
My Camaro had the exact same problem and it was a vacuum hose leak.
If it hasn't been converted to R-134 if will have to be
There is no such thing as a 1992 IROC Camaro
should be the same thing.
Yes
Yes
will a 3.8 engine from a2002 Camaro interchange with a1999 camaro
Yes.
The 1992 Camaro takes 4.0 qts without filter change
Yes
There was no SS camaro in 1992.
No, 1982 to 1992 are the same body stile, 1993 and up it changed
Yes