P0430 Catalyst Efficiency bank 2 problem?
I have a 1999 Ford Taurus SE v6. I had to replace the motor because it blew a head gasket. When I got the car back with the new motor the light came on. I just changed the bank 2 cat today (the one closest to the front). I had the code P0430 cleared. I went 36 miles and the light came back on. The car sometimes is hesitant when I crank it first thing then it clears up and runs smooth when it warms up. Is it now the 02 Sensor? & which one do I supposed to change? I'll consider all answers.