Exhaust sensor help - is my truck missing something?

I bought the truck used and the exhaust looked like the pics below. It's tough to find stock exhaust pictures to compare what I have to how it's supposed to be so I'm not sure if what I have is correct or not.

I've had the truck for a little bit now and there are no real issues except it always seems to run lean. As such never really had much power so I've replaced or cleaned everything in the intake, vacuum hoses, spark plugs, wires etc and it still runs lean.

From the down pipe I see O2 sensor #1 and that seems right. I don't know what that canister is in the second picture but between the canister and the cat it seems like there should be another O2 sensor and there isn't one. O2 sensor #2 is after the cat in the last pic. Also, in the last picture there is a section of pipe welded in and that isn't stock so what is missing?

Question: Is the exhaust missing something that could cause the truck to run lean? Or anything that looks out of place to you guys that are used to working on these. Thanks for the help!

 

https://www.tacomaworld.com/threads...st-on-my-1997-extra-cab.477234/#post-14492663 read post #9 and check the links for pictures

 

i have a 2002 3.4 and just replaced the pipe in your last pic. its a short piece of pipe with an 02 sensor.

 

At some point someone got the wrong muffler tail pipe for the non- California emissions and just welded in a piece of pipe rather then correcting the mistake .

Your Mil should be on all the time unless you have a cheater box installed to the rear O2 sensor harness

 

the "canister" is the first CAT (dual CAT on '00+ models to meet CA spec). the shield looks caked with mud or rusted a bit. should be silver and maybe aluminum but mine is still silver metal.

I did the same for mine as your last pic. due to rust the flange was never going to hold another piece of mid-pipe. I cut the flange section out and used a solid section of pipe to connect. My CEL is no longer on as it was when the seal disintegrated. as long as there are no big leaks it will be fine. short of replacing the CAT or having someone weld a flange piece on you should be OK

 

O2 sensor is on the other side of the part you circled in the last picture. LOL

 

Thanks for the link, very helpful!

Cool so it's only missing a flange right there that's not a big deal. I didn't realize there were 2 cats, good to know for sure. Thanks!

Yeah, that's the O2 sensor #2 I referenced. I was curious if there was a sensor missing between the 2 cats but apparently not.


Thanks for the help guys!

 

from what I've read from smarter people than me, the rear O2 is just for assessing the gases coming from the CATs but does not factor in the fuel trims. the front Air/Fuel (O2#1) sensor does.

if it's a welded piece it should be structurally sound. mine is just clamped in. passed inspection, tho I don't have to do emissions

 

The second sensor is just to measure cat efficiency. If you don't have a CEL then there may be some type of bypass installed and you have nothing to worry about.