please help

[erik671]

My check engine light is on with the code: Low catalyst efficiency. I first changed the downstream O2 sensor, and that didn't fix it, then I replaced the cats, and surprisingly that didn't fix it. What else could cause that code??

Please help, I am at a total loss.

-Erik
'96 Explorer XLT 100k

 

[aldive]

The following link may be of some help: Dead Link Removed

Good lucj