HI, I recently failed the emissions inspection on the low speed: HC 825 / CO 8.30...what could be causing this? I have been told it could be my CAT or my o2 sensors, I was also told to just get a tune up.
I really don't want to get ripped off. I just need to get an inspection sticker!
HELP!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

1992 300ce
artic white
121k