I'm trying to track down this minor surge, but I'm running up against some confusion. At constant speed, 30mph, fairly constant TPS (as steady as my foot can hold the throttle) the car seems to be switching from the high octane table, to the idle table...at least I think that's what it's doing. When it's on the high octane table there's 41 degrees of advance, and the car is smooth as glass, then it ramps over to the idle table for some reason, and it seems to oscillate between 18 and 22 degrees of advance, and it's very noticeable in the drivers seat. LTFT remains very steady while it's doing it and the behavior of the STFT even appears very similar when it's smooth to when it's surging.
It seems to be when my foot gets to 14% ETC, but 15% appears to keep it smooth. Ignore the wideband data, the sensor isn't in the car.
I disabled spark smoothing for now, because I haven't gotten a good grasp on tuning that yet, and it makes some surging far far worse when it's enabled.
Any advice? Check between frame 6500 and 6900 for a really clear example of it happening.