I think the same thing happened with my car the last time I smogged it. Everything was way below max except HC, which was right near the max. HC's come from unburned gas. The cat is supposed to turn the hydrocarbons into CO2 and water. Maybe you're running a little on the rich side, or the cat isn't completely doing the job?
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2015 Ford Mustang GT Fastback - Ingot Silver - 6M - Performance Package - Gibson Catback, JLT CAI, FR 47lb injectors, BAMA E85 tune, Eibach Sportline, BMR wheel hop kit, UPR oil separator, Steeda shifter bushing/bracket
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