We are in NJ. yes the check engine light is one. We did put the sensors back on, but we put the catback on about a year ago and the light just recently came on
Go get the codes checked and find out what is causing the light to come on. It might not have anything to do with the catback. The only thing failing you is the fact that the light is on. http://www.miracerros.com/mustang/2000_index.html
that site can tell you what each code means. I know it says 2000, but it'll work for OBD-II, so it'll work for that 01.