Welcome to the club!
I had fits getting my '86 to pass emissions too, so I can feel your pain a little.
It might be a bad cat, it might not, but chances are a new cat will get it to pass (even if that isn't the problem).
Could you license it in PA instead (or are you in an emissions county)?
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1986 GXL ('87 4-port NA - Haltech E8, LS2 Coils. Defined Autoworks Headers, Dual 2.5" Exhaust (Dual Superflow, dBX mufflers)
1991 Coupe (KYB AGX Shocks, Eibach lowering springs, RB exhaust, Stock and Automatic)
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