[silverbullet]

I have been running stage 1 on the OFT for about 50k miles without issue and then over the course of the last couple weeks have watched my fuel trims in closed loop get progressively worse. At steady state partial throttle I'm seeing anywhere from +11 to -11 over the course of just a second or two (I have the maf scaling pretty dialed so normally I never see over 2%). I have gone through 3 tanks of gas from different stations and have checked the intake track for possible vacuum leaks. Only mods are a perrin inlet tube and a catback. I'm thinking mabey the 50k of running rich on a tune has killed the o2 sensor? Idk, any ideas would be greatly appreciated.