2 new cats, all o2 sensors replaced, still P0420

[breezd]

Well, as the title says, I'm gettin a p0420. I have replaced ALL o2 sensors, and 2 of the Cats. The car APPEARS to be running fine right now...

98 'tour SE
2.5 v6
113k

I tried searching, but could not find anything that really helped ME. Any help is appreciated... thanks

 

[BrApple]

which cats where replaced ... was the main cat replaced twice? the wrong pre-cat might have been replaced ... chances are you might need the pcm reprogrammed to widen the limit for P0420 and P0430 codes ...

 

[breezd]

according to the mechanic that did the cats, he replaced the 2 "difficult" ones. He left the "easiest" one for us to do...

Another note to add, since he did the cats, there has been this sound. it almost sounds like a hole in the exhaust, but it isn't that loud. Its kinda a "put-put-put" sound... thats the best i can describe it lol

 

[CSVT1214]

The "put put put" sounds like an exhaust leak.

 

[projectSHO89]

The "put put put" sounds like an exhaust leak.

And exhaust leaks will cause cause skewed O2 sensor readings depending on where the exhaust leak is at.

Find it.

Steve

 

[Tony2005]

according to the mechanic that did the cats, he replaced the 2 "difficult" ones. He left the "easiest" one for us to do...
...

Drive up ramps or put on jack stands and go under. You should be able to tell if the radiator side (Bank 2) or firewall side (Bank 1) or main cat were the ones replaced. Now, you're just going by assumptions or guesses. Precats or cats are too expensive to rely on assumptions and guesses.