Can you identify this part/hose?

I saw this hanging from under my truck in between the muffler and cat. Does anyone know what this is? Sorry the picture isnt great but its a spicy 9 degrees out right now

 

O2 sensor... Should be a threaded hole in the pipe after your cat that it goes in... Idk what would cause it to fall out.

 

Is the truck louder as well?

 

That's the primary sensor, goes before the cat, and is held in on two studs with nuts. The studs probably snapped off from rust.

 

^^^this^^^

 

Weird thing is, I've seen this happen before. On the Tacoma I saw the nuts somehow backed off. We just put on a new gasket and nuts and away it went. Never threw a code or anything.

 

if studs did not rust off,new gasket and DOUBLE nut it.

 

No, that sensor is after the second cat..

My studs completely rusted away, did a temporary fix using some pipe clamps, held for a while, but ultimately had my muffler guy weld in a new bung

 

Truck is louder but my muffler is also shot. Taking it to get checked out this week

 

I have seen some use bolts so reach under there with a mirror and see what it looks like, you might just need to replace the bolts and put a new gasket on it.

might save you $100

then again is this a new to you truck? maybe the previous owner bypassed the o2 sensor and it was just tied up out of the way and slipped down just now. people do some strange things sometimes.

 

That is O2 sensor 1 of 2, as an OBD scanner would read. Your truck will sound louder under load and most likely throw an P0136 or similar code for O2 sensor failure.

I found the same thing when I noticed my truck get louder under load a few hours into a 30 hour roadtrip. There are two studs coming from the exhaust where this mounts in, and two nuts holding the sensor onto those studs. Those nuts rust out very easily and the pressure of the exhaust and vibration can then blow that sensor right out of the exhaust.

Just get two new nuts (stainless if you can find them) and a new gasket ($5) and tighten it back in.

 

It actually looks like it was taped up to the frame of the truck and all the recent snow maybe got the tape wet

 

Thanks for the advice, are you talking about a crush gasket?

 

If that was taped up to the frame, what was in the oxygen sensor hole in the exhaust? Did you just get this truck?

I don't know if I'd call it a crush gasket, but this is what you want.
The old gasket may still be on exhaust so check for that first.

http://www.ebay.com/itm/Toyota-Oxyg...2003|Model:Tacoma&hash=item519acbe929&vxp=mtr