NOx is ur egr valve. CO could prob be fixed with a good tune up and a new cat never hurts. There is also this stuff called "guaranteed to pass emmissions" at like advanced auto and that stuff works GREAT and its a coulpe bucks and is like a fuel treatment and if it still fails u get ur money back...thus guarenteed to pass lol but ur prob gonna have to do something with ur egr valve to get the NOx down. it might just mean cleaning the tubing or a new egr valve