2006 GT with a hesitation

[46addict]

From my limited understanding, low o2 voltage points to a lean mixture which sounds right if the sensor is behind a functioning cat. The cat is supposed to burn off emissions with heat so it would make sense for the downstream readings to be leaner. The spiking should still occur, just not as often as the upstream o2s.

 

[rickf]

The spike I am talking about is showing up on a data log as an 1850 volt spike. Did it before and after the cat and O2 replacement so that has to be induction from somewhere. The problem I am having is one side is reading 750, as do all my other vehicles and the other side hovers at .04. That is the side that had the melted cat. I don't want to destroy another one but I am afraid I may be overthinking this. There is obviously something wrong since the two sides do not agree. But with just replacing the cats I don't know if it is an engine issue or a cat issue. Summit is working with me and I actually have another system here already, I just want some answers before throwing parts at it. And yes, I did swap the O2 sensors from side ot side and the readings stayed the same.
A lean mixture is actually high in O2 and a rich mixture is high in hydrocarbons. Think of it as lean is too much air and not enough gas.

 

[TheGing]

The spike I am talking about is showing up on a data log as an 1850 volt spike. Did it before and after the cat and O2 replacement so that has to be induction from somewhere. The problem I am having is one side is reading 750, as do all my other vehicles and the other side hovers at .04. That is the side that had the melted cat.

A voltage spike is usually an indication of a magnetic field collapse, I'd inspect wiring for some interference from other sources. Any resolution with this problem yet?

 

[Juice]

What about a bad knock sensor on that bank?

 

[rickf]

I thought I updated this page but I guess I forgot. I had opened a new thread on the problem for some reason and that was the one I put the solution on. The solution to the problem turned out to be replacing the catalytic converters. Even though the upstream converters were not throwing a code the left downstream one was. Technically all that is is a monitor and has nothing to do with the drivebility. Well, either it does or the upstream sensors were not reading as fast as the needed to be. Once replaced it took about 300 miles for things to settle in even though the KAM was completely reset. I found that interesting because I was originally thinking the problem was not solved. Actually I only replaced them because I had to to get through inspection. It runs fantastic now and that was the only thing I changed.

 

[Moostang313]

Rickf, thank you this information is like gold to me, hopefully. I’ve had the exact same issue that you have explained. I’ve thrown some parts at mine though not as many as u. The next part I’m throwing at it is headers and catted xpipe.