I just bought a 2003 Tib GT that was straightpiped and doesn't have a CEL on. Is it possible my ECU was flashed and I need it flashed back to stock? Or can I just throw a universal cat (needs to be CARB compliant, unfortunately) in and it'll be okay?
Are just the resonator and mufflers deleted or does it have aftermarket headers? 03's are less sensitive and sometimes won't throw a CEL so you should be good. Unlikely it was flashed there really aren't any.