Has anyone had there primary O2 sensor go bad? My cars has been acting up lately and I suspect it's the o2 sensor. I'll be driving at a slow speed in vacuum and all of a sudden my air fuel will lean out to around 17-19 and the car will sputter. But mostly it will completely cut out just like a fuel cut. But once I let off the gas and get back on it the car seems fine. Mileage is 39k mods Sri/tip/tbe/Ptp Sst and wga/Ptp pump/Hks ignition/Cobb ap on stage 2+. What's weird is that it just started happening when I installed the Sst. Any have the car do this? Maybe o2?