98 740il- problems with cat. converters

[mm1791]

I hope someone can help. I have a 1998 740il, when the car turned 85,000 miles the ck engine light came on and the car ran very rough under wide open throttle . I had the car looked at by BMW dealership who checked everything then told me my CATALYTIC CONVERTERS were bad. I had them replaced with aftermarket converters and after 7,000 miles they have gone bad. It's back in the shop now, but if anyone has any advise please let me know. Also the car had a full tune up at 86,000 and the o2 sensors were said to be good.

Thanks,
Mark

email- [email protected]