u/New-Protection2373

Had a terrible exhaust leak in my 1997 Camry so I bought some after market walker exhaust parts and switched the old ones out , the cat flange was completely rusted out , one of the 3 cat to manifold bolts was stripped so I tighten it the best I could to try and seal the gasket , it sounds a thousand times better but I ran a obd scan tool and it said the the o2 sensor on the mid pipe is reading 0.0 and ltft1 is at 21.9 percent , no check engine light yet but the o2 sensor is pending , should I try and fix that manifold bolt , is that the cause of it running lean? that the gasket isn’t seating properly