Not necessarily. The downstream O2 sensor on a 1996+ year model Camaro is only a catalyst monitor. It does not control fuel consumption. It will, however, set the MIL and have it remain on until fixed. The upstream sensors are what directly and most adversely affects fuel consumption in closed loop. And cutting the converter off does not do neearly as much as people would like to think-- other than giving the system an unnatural sound. The only time I'd advise a cat gut or removal is for a temporary repair. As I've said before, an EPA maximum fine is $50,000.00, regardless if your state does emission testing or not.