My 01 3.0L failed it's smog test today. It read 0.65% CO @ 15mph,(passing is .47) and 0.61% @ 25mph, (passing is .44). I found a p0430 code (bank2 cat). Could the cat be dirty? I poured 3 pints of alcohol into 1/4 tank of fuel and drove it 25 miles before the test. The alcohol leans out the air/fuel mix and I've had really good results with this method on all car makes in the past. I do need an oil change though. any ideas?

 

The PCM will adjust in seconds if not faster so I think the alcohol is pointless (but may damage hoses & seals). It's running VERY badly to have so much CO so go about diagnosis via OBD or guess at costly parts swapping.

 

You have a problem. Don't throw stuff at it. Fix it!

Erase the codes you do have. Drive some more and check again. Have you been driving with a check engine light on?

I don't know what a dirty cat is??
It either is working or it's not. You can't clean them, only replace them.

You could have an O2 problem also. To check that swap the O2 sensors from side to side and see if the code follows or not.

Finally has the car had any maintenance done? Like coils and plugs? These are wear items and if you don't know then consider changing them. They degrade slowly over the life of the car.
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