I have an LS3, E38, cam, heads, converter, etc...all N/A on pump gas...
When I am cruising at highway speeds and cut the throttle back to idle and coast down, I noticed the wideband gauge reads .85. Strange I thought. So when I look at the logs. I see that indeed wideband shows rich, and the narrowbands agree since the voltage is high/rich (850 mV). Yet the STFT + LTFT is showing +32%! I cannot understand the ECU would keep dumping in fuel when the O2's are reading rich. And this rich condition may last 10-20 seconds during a coastdown too.
COT is disabled
DOD is disabled
DFCO is disabled
Desoot is disabled
I have checked and resealed for exhaust leaks and didn't see any changes. I guess I will try to disable LTFT and see if that changes anything. But other than that I am out of ideas.
throttle chop.png
https://imgur.com/a/QaUw0dI