Massive timing advance fluctuation at low revs

[OldSkoolGP]

I've finally had enough with my car shaking back and forth when I'm trying to drive it around at low revs in the city. I'll be going along fine then all the sudden the engine will begin to shudder and the whole driveline starts to clunk and the car surges back and forth. I thought maybe it was a fueling problem with my bigger injectors. I recorded a log file with HP Tuners tonight and it turns out that my timing is jumping wildly with minute throttle input, anywhere from 14 to 34 degrees.

I recorded a log file and I'm uploading my current tune as well. The problem occurs at frames 350 and 2930. What I notice is that the Torque Management Advance PID is adding timing when this is happening, but I think it's really taking timing out because the overall advance seems to drop in proportion to the number it's displaying. What is causing this? I hope someone else has seen this and knows how to fix it, it's driving me nuts!

[SultanHassanMasTuning]

mods?

[MikeOD]

Looks like torque management advance is yanking timing and then giving it back. Not sure why as you've got that all maxed out.

Have you tried turning off spark smoothing? You could also try zeroing out the Spark Retard vs. Torque Reduction and Torque Loss % vs. Spark tables, since it's an M6 and you've got torque management all set to max torque values anyways.

[MikeOD]

Also, if you turn off traction control do things run better?

[Tally TransAm]

Have you tried turning off spark smoothing?

try this

had the same issue with a c6z i tuned, turning off spark smoothing corrected it

[OldSkoolGP]

The problem still occurs with TC turned off. It's a heads/cam motor, but only a small cam, 220/224. It's done this since the cam was installed. I will try turning spark smoothing off and see what that does. My only other thought was every now and then when I start the car I get an ABS Fault on the dash. I never get it when I'm driving, but sometimes when I accelerate hard in a gear it'll say Low Traction even though I'm not spinning a tire. Could a flaky ABS sensor cause this?