My catalytic converter keeps burning out, I have replaced it 3 times and the same thing happens. I drive it for a few days or so, the check engine light comes on then I take to mechanic and he puts in a new converter. the first time he just put in a converter. the next time the coils burned up and he replaced them, the next time he replaced the computer. the next time he replaced the converter again. now a week later the engine light is on and the car radiator fan comes on.
Should you be able to supply the check engine light code I would be happy to help you narrow down the problem. I would think if you are unhappy with the results of the money you are spending you might consider going elsewhere.