well thats been a very long day. I looked over 8 Vibes in the junkyard, found one AWD, same year as mine. I didn't manage to get anything from it, but at least I know it's there.
The Canadians got back to me, and yes they will ship the Unholy Exhaust components to NY. So that's good. I could get manifold/cat, 2nd cat/pipe, and even add in the midpipe/resonator for about the same price as partsgeek lists just the manifold/cat.
So that's good news. But its not only illegal to buy or sell in NY, but also illegal to install. So unless I can tackle this myself, I'd have to find a shop willing to install without asking the wrong questions.
I pulled the top o2 sensor today, and could see the manifold/cat looked fairly good from what I can see. No carbon in it. I thought I could see a few of the pores plugged up. Obviously you can't see much through the sensor hole with a flashlight.
So, I went ahead and seafoamed right in to the upper cat, through the sensor hole. I used around 1/2 a can of the upper engine cleaner seafoam.
The car seems to have more power now, smoother, but this has not stopped the P0420 coming back. People who have done it have mentioned they've used a full can or more in multiple attempts and it has fixed the code for them, sometimes for a year or more.
But watching my scanner app, the #2 sensor has become much less stable, jumping all over more frequently, and when it is stable, it reads much higher voltage than before.
Being a hack, I'm not really sure what it's supposed to do. I thought #2 sensor was supposed to stay low, and that indicates the catalyst is working. This is what happened post-lacquer treatment, it was very stable around .2v, with only the occasional trip north of there.
I'm wondering if what has happened is, blasting out the top converter has sent a lot of junk into the second one.
So I might pull the #2 sensor tomorrow, and do the same thing to the lower cat, except I'd be blasting backwards into it which is less optimal. I suppose I could drill a hole just upstream of it, and then plug it with a screw, or use the exhaust wrap I have onhand.
I've got enough money into the car, and relatively little money left, that I'm willing to keep at unconventional but old-school solutions to just get a year or two out of the deal.
It just sucks that a car running so well, indeed improving with the cleanings I've been giving it, has an illegal exhaust because of what? I feel doubly abused by not only a dishonest seller, but the unthinking State that would send 35mpg cars to the junkyard and call that "green".