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Catalist efficiency below threshold

I was app. 10 miles from home & engine started missing & went into limp mode & yes the light flashed . I limped it home anyway & now have a PO430 code . # 2 spark plug died & caused this , danged plug didn’t have a hundred miles on it since new . Replaced that plug & everything’s fine except that code . Vehicle runs great . Anyone think cataclean or a similar product is worth a try ? I’ve also read an 02 sensor could cause this code .

It may take x amount of miles and or starts for the code to clear. Both are possible, no personal experience with cleaners for the cat.

The flashing Check Engine light was reporting that if you continued to drive the vehicle, there was a possibility that the catalytic converter could be damaged. And if the substrate of the catalytic converter is cracked it reduces the catalyst efficiency.

Some will say replace the down-stream O2sensor. But this is like killing the messenger because you don’t like the news.


Some people swear by those catalytic converter cleaners in a bottle, others swear at them. Probably won’t hurt. As @Barkydog wrote, the code will continue until a certain number of “drive cycles” occur. You could clear the code with an OBD II reader and see if it returns.

There are a couple brands that get pretty good reviews . Think I’ll try one . I did clear the code & it came back .