my car since i bought it new would give off a sulfer smell with full throtle accelleration. i've always thought this was caused from a lean condition which would inturn would heat up and cause burning in the cats which gave the odor. correct me if i'm wrong?

over the last month i've switched my muffler and assembled a cai and now the odor has gotten worse. is my thinking correct about leaning out? if so the tvt250 items sould help reduce the smell?