There should be an error code if it's an O2 sensor. Depending on whether it's an upstream or downstream sensor, i.e. #1 or #2, it might also be responsible for the poor running. An upstream or #1 sensor affects the mixture whereas the downstream sensor (it's only there to check catalyst function) does not.
Any OBD II code reader will tell you.
2013 GT Premium Brembo
MGW, Blow Fish, AM Hood Struts
Tinted, Borla Touring AB, ProCal Tune
Full Shelby/Kicker Audio Upgrade