my 97 ford taurus 24v DOHC has the CEL on. I went to AutoZone and pulled the code P0430 Catalyst System Efficiency Below Threshold Bank 2 Rear. Could a bad O2 sensor cause the engine to run poorly when accellerating and idling. If I accellerate slowly, it wont be noticeable, but if I accellerate normally, it is much more evident. It's almost as if not enough air or fuel or both (intermittently) is being delivered to the engine for optimal performance. Could this be causing my car to stutter when accellerating to highway speed or while idling. Once I am up to speed, everything smooths out.