I know Miami Son has a v10 with the california emission set up so I guess he will be able to answer this question. I took my truck to the auto parts store to get the check engine light read (which has been on for years) and the results were two 02 sensors acting weird. The first was Bank 1 sensor 3 (the one in the cat?) and the second was Bank 2 sensor 1( the one right after the cat?). The bank 1 sensor 3 had high voltage and the bank 2 sensor 1 had slow response and high voltage. I replaced the Bank 2 sensor 1 (assuming it is the one right after the cat, it was melted) with a downstream bosch direct fit, but I don't know which sensor to get for the Bank 1 sensor 3 because the auto parts people are saying that the truck only has 2 bank 1 sensors. I know it's upstream, so will the other upstream sensors work for this one? Apparently the CA trucks have 4 o2 sensors rather than the lower 48 trucks that only have 3. Maybe someone has a part #? I don't really want to do the universal sensor because of the room for error. Thanks for the help.

 

And I thought I might add the other things that have been going on with the truck since I have been trying to fix the crappy idle and bogging. I replaced the TPS with no result or change. Replaced the IAC which made it worse. Returned the IAC and got a better one for the same price. Still no change. Replaced the downstream o2 sensor... no change. Poured a whole thing of seafoam into the IAC hole while idleing, made it stall twice. Only a very little improvement. Drove it up to North Georgia on friday and it ran ok for about 60 miles and then all hell broke loose. It started with a spot in the throttle where if I pressed just a little bit mor it would take off like it had a turbo and accelerate really hard, but if I came back down it would be normal. Then after a while that spot made it jerk violently like it couldn't make up its mind. Then a little later it wouldn't go above 55. I took OD off and it would just bog and occasionally rev up enough to let me get up to 65. I think that was the IAC sticking. When I stopped at the gas station it stopped doing it for about 20 minutes and then started again. When I got into the mountains I realized that I had forgotten to connect the hose that is connected to the air intake. I stopped on the side of the road and put it back on. It was still running really boggishly. I got up into the mountains and the check engine light came back on. Then I drove it around in the mountains for 2 days and all I noticed was a small whistling sound. When I came back down the mountain to go home the truck was cured. It is running really well now. It feels like it has more power than it did before I replaced all of those sensors. I'm going to replace the other o2 sensor as soon as I know which one to put there. I also got the gasket I need to take the TB off and clean it.

 

I fugure someone is eventually goig to respond to this so I'm goning to ask yet another question. My cat is actually making a ton of noise. I always thought it was a sound from the muffler but it is the cat making a super loud buzzing oise during acceleration. Now I want to just have it cut out and replaced with the y pipe I bought. I don't even want to put another o2 sensor in place of the one in the cat. My truck is a 96 but I wonder if the fastman o2 simulator will work anyways. It does say it is for 97 and up. I need to figure this out, cause I know it is robbing a ton of power and cauising all of the idle and bogging problems.

 

I believe only the V10s with dual exhaust have 4 sensors. Mine has single exhaust and 3 sensors, so can't really say which is which. I know the downstream sensor is different from the 2 upstream sensors. Also, you won't pass smog with a gutted cat.

 

He's in georgia

 

Didn't see that, just the mention of a CA emission vehicle. Why does he think mine is relevant?

 

You said yours has the CA emissions meaning the single pipe...... Anyways, I am severely confused. I have no idea why it has 4 o2 sensors. There are one on each side after the manifold, one in the cat and one after the cat. WTF????? Ill just put an upstream sensor and hope it works. Thanks.

 

You only have 1 CAT
Mine has 2
2 headers into 2 cats into 1 muffler into dual pipes(I added the dual pipes the rest is stock)
Are you getting any ping?

 

No ping, just a buzzing sound during acceleration. The buzzing is really loud and I could never really tell where it's coming from until yesterday when I rolled my window down and leaned over to put my ear down as close as I could to the cat. I'm convinced that the cat is making the noise. I still haven't ordered the o2 sensor (Bank 1 sensor 3) because I don't know if I need to have it at all. I'm curious to see what will happen if I simply unplug it.....

 

Hi, I know this is 10 years later. But hopefully, you have an answer to this. I have the cat with a built-in 02 sensor, (walker 81512), I want to replace the o2 sensor in it, but I don't know if that is upstream or downstream. If upstream, right or left????? Any help?

Both headers go down into one cat (dual in, single out) to a 4inch pipe out to muffler.
The current setup is 4, o2 sensors: one o2 in right headers, one o2 in left headers, one o2 installed on to the front of the cat, one o2 after the cat.