6.0 M6 - Return To Idle Issues

Hello All,
I'm very new to the forum and tuning in general, but I'll try to be a specific as I can with my issue. The car starts/idles and makes great power throughout the power band. The only issue I see is when I'm coming to a stop, at times I leave the car in gear while decelerating before pushing the clutch in and begin to brake for the stop. It is when I push the clutch in after "engine braking" that intermittently the engine will drop RPM faster than normal and at times will die all together. The issue is with the IAC values dropping when decelerating in-gear, so when the clutch-in action is performed, the engine is starved of air and dies. I've attached my latest tune file and a log showing the issue. See minute 4:10 and 9:55 and compare the IAC values to other points in the log where I'm coming to a stop (see minute 7:30). I believe the correction lies in the throttle cracker/follower tables, but not sure where to go from here.

The correction will lie in the throttle cracker/ follower tables. You can try adding 20% to the lower area of the cracker and pay close attention to what it does when you clutch in and let off the throttle. What ECU are you using?

Hello and thank you for replying to my post. I plan to try and make some changes and evaluate the results later today and tomorrow. I will try adding 20% as you stated. I'm running the GM -896 ECU.
I was looking into another tune file for a 2005 Silverado manual transmission. A few major differences in the tune included throttle follower delay values of 32 seconds. I wonder if that is how GM dealt with the issue of the -896 (being an auto transmission type ECU) is they just delay the throttle follower until adaptive idle takes over at a slower speed (~3-4 mph).

05 Silverado is ETC throttle body. No IAC so not good for comparison to a cable throttle body calibration. And the 896 was used with both auto and manual transmissions. Just different calibrations.

I'll verify the year of Silverado I pulled the tune from. Regardless, I'm looking for feedback on my theory of delaying the throttle follower. My thought is; after the throttle blade closes, delaying the throttle follower should keep the IAC counts higher while slowing the vehicle down (in gear), until the adaptive idle takes over due to the vehicle speed trigger. Maybe this is how they were able to use the -896 for both auto and manual transmissions?

I intend on trying this and LSandlteditor's suggestions on cracker/follower tables. If there are any other suggestions, I would be willing to hear them also.

Hello All,
As an update to this, I've been logging and systematically changing values in the throttle follower and throttle cracker tables, along with base idle airflow. It seems that the throttle follower does not do much for me on this issue, however I can see a difference when I make changes to the throttle cracker. The sample tunes I've been reviewing with manual transmission have very high values for the throttle cracker (10-15 g/s) when compared to the auto transmission tunes (1-2 g/s). In summary, it seems to be getting better, but the more I drive, I think the more the PID's begin to affect return to idle issue again. I'm about to start diving into the PID's a bit more, anyone good at looking at PID settings and giving some pointers?

For those that have these issues in the future, I believe I've come up with a solution;

Using the throttle cracker airflow table, I've set appropriate values for airflow just by trial and error (my setup liked ~2 g/s). Then, I set the throttle cracker airflow decay to zero, the enable speed ~5mph and disable speed at 4mph. This will leave the throttle cracker open anytime the car is moving and allow adequate airflow when the engine RPM is returning to idle.

The car has since not had issues dropping RPM too fast due to IAC counts being too low when letting off the throttle and taking the car out of gear.