WTF - What Is Next?

[Digital Corvette]

Long time lurker, now need to tap into your brains.

2000 Corvette M6, Street Sweeper HT cam (228/232 .612-.600 111 +3 so overlap of 8 degrees), 243 heads, LS6 intake, XS Power 1 3/4" LT with high flow cats, Corsa axle back, Vararam CAI, ported throttle body, Ford SVO 30lb "Red Top" injectors (Ford PN M-9593-BB302) rated at 36lb/hr at 58 psi.

Street tune (no dyno) by a local guy. Some drivability issues made me go get an MPVI2 (AEM wideband on the way). Burn 91 octane, which is the only gas reliably available around here, so was tuned for it.

First time log today was surprised to find the engine running on the low octane spark table. Was shocked to find that the low octane table had MORE timing than the high octane table. So WTF. Also, log shows some sporadic KR that I don't understand why it is happening. STFT also pulling fuel out pretty consistently but I will wait for the wideband to play with fueling.

What is my next best step? Switch the timing tables around (or copy low to high and then reduce the low by -4 across the board) and modestly decrease knock sensor sensitivity (best way to do this??)?

Thanks in advance for your help.

2 log March 20. 2021.hplInitial Tune By Wally March 721.hpt

P.S.
Main drivability issues 1) very jerky at 1650 RPM at low throttle settings 2) warm start (after sitting) fires and then stumbles for 30 to 60 seconds.

[5FDP]

At a quick glance on the timing, probably go back to a more stock like table. The high needs more timing than the low.

The giant steps it has at 1200, 1,400, 1600, 1800rpm is not good for cruising, it shouldn't jump 15-20 degrees like that. I would find a stock timing curve and use that for reference on a better looking timing graph.

I wouldn't go hog wild with other changes until you fix the fueling, if the STFT are pulling a ton of fuel then the airflow is wrong and needs fixing. A majority of driveability issues get fixed if the MAF airflow fq curve and both VE tables are tuned correctly. It will even help with cold start and warm start issues if the fueling is correct.

[Digital Corvette]

Thanks. I do have a stock tune so can swap in timing tables. Any thoughts on the KR I am seeing ... is this knock enough to force it to use the low octane table?