2003 C5 6 Speed. Stock car, Cat delete, AEM 30-0300 wideband.
I tuned the MAF and VE tables separately with fuel trims off.
When I turn the FT back on the car pulls ~8-10% fuel out right away. Now since both narrowbands agree I'd want to think my wideband is wrong or I have an exhaust leak after the O2. The only thing making me thing differently is if I command the desired AFR with my VCM scanner and Closed Loop disabled, My wideband almost perfectly follows my commanded AFR. It's as if both my narrowbands are skewed and want to cycle around 16.6:1 AFR.
I had an idea that since the stock stoic is set to 14.63 and modern fuels have more ethanol than in 2003 that changing the stoic to 14.08 would fix the issue, but when I tried it made no difference.
I'll post my stock file, current file, drive log, and idle log of me controlling the commanded AFR.
JAMES C5 V003 MAF+SD FINAL+PE ADJUST.hpt
1G1YY22G235125468 2003 Corvette 6Speed stock file.hpt
weird o2 drive.hpl
idle log, scanner afr control.hpl