[Accuracy*1]

first off a cat should not cost you 1,000 bucks... if i were you i would put a fat cat or (high flow) on you car they are not expensive and you still will be able to pass emissions... Now that could or could not solve the rotten egg prob but i would start there ... now on your check eng light i would go to a hyundai web site and get the ecu codes and then get the code your ecu is throwing and go from there... Or just sell your hyundai and get a honda!!!