and she heard a noise and then the truck would barely drive. I went and checked it and i lost the exhaust pipe between cat and muffler (right below the second row) I also found 4 bared wires that had been ripped apart.

Exhaust broke loose and wrapped around drive shaft and ripped the sensor wires apart and threw the pipe somewhere?

So i am assuming that there was an oxygen sensor located on that portion of exhaust that is now lost.

I thought no big deal I will just drive to a muffler shop and get it fixed, but the Ex would barely move. So i guess i will have to tow it unless someone knows how i can get the truck to run missing the pipe and sensor.

My questions are:

Is that an oxygen sensor that goes into the exhaust pipe?

If so, can i just buy the sensor and pigtail, wire it and then drive to get exhaust fixed?

Is there a way for me to drive it without wiring in a new sensor instead of paying for a tow?

2004 6.8L limited

Thanks for any help you can provide!

 

It sounds like you lost your 3rd (after-cat) O2 sensor. I didn't think it would cause that severe of drivability problems, but then again, neither of mine are equipped with the 3rd O2.

 

Thats my consensus as well.

See my EXTREMELY blurry photo for location of the post cat 02 sensor. And Psyclopse is right, no driveabilityy issues will arise since that sensor is only used to monitor catalyst efficiency and is a strictly emission system bound component.

 

Have you looked to see if any of the wiring to the trans was damaged?

 

The Ex ran fine until the dropped exhaust pipe and now it doesn't want to drive. Would the missing pipe between cat and muffler cause it to run bad? Back pressure or something? It is hard for me to believe that there are two separate issues here. Although it wouldn't surprise me either.

 

Might need to pull DTC's to figure out why it doesn't want to move now. Stebs might be on to something with the transmission wiring being screwed up. Maybe shift linkage was knocked out of alignment and the trans isn't shifting? Could be a lot of things...

 

I didn't, it acts more like it is not getting fuel or is starved of air. I assumed that without the sensor and the bare wires maybe the computer was overcompensating or maybe something shorted out.

 

Check engine light came on, so i will go see what codes come up, obviously the best course of action. Didn't have my code reader when i went there earlier.

Thanks for all your help, just trying to get as many ideas as possible so when i go check it out tomorrow i will be better prepared,

 

That statement by itself usually doesn't have a good outcome

 

Too true Michael. Are you certain nothing else happened to cause the exhaust break? Seems unlikely unless something big was driven over?

 

No. When I bought my truck, it was straight-piped by the previous owner- no cat, no muffler. It was loud as can be, but drove fine. I stuck a muffler in there, but no cat. Still drove fine. Then, last year, the muffler I installed decided to split at the seams while going down the road, and as a result, ripped the entire exhaust off from about where the cat would be, on back. Drove it like that for 2 weeks- again, loud as can be, but no major drivability issues.

There isn't a whole lot of transmission/transfer wiring on that side, but there is some. Check it for damage. I guess it is possible that the O2 wires shorted against each other or shorted to ground during the destruction, thus screwing up the PCM.

 

I can picture that violently ripping the exhaust from a truck could have shaken the cats loose internally. You may have a plugged exhaust.

 

I fixed it for you.

 

I would do a through examination of the underside.
Wrapping exhaust around driveshaft? Really?

How did you get it off the driveshaft?

I would look at the fuel line, as exhaust pipe wrapping would have hit both sides and roof/floor. Possible crushed fuel line.

Inspect brake lines too and wiring that goes to rear of Ex.

 

Guess I should add that when I was halfway through my header install I had to drive it to my buddies shop that works at the local DOT and the headers were leaking and I was running the headers and Y-pipe only and drove about 8 miles with no issues. I just did every little thing I could to keep it from shifting early