large rpm dip approaching stop...seems random....how to tune it out?

[rcodea1]

could use some input on how to tune out this rpm dip....all the way down to 400rpm. base idle is 720, and i do get error of ~50rpm up and down when stopped. This major dip seems to be random....doesnt seem to correlate with hard stops....but is persistent with changes to Airflow Min for 2nd gear, Coastdown or Idle Followers. there are other dips as well, but none as drastic as this one.

Thoughts on possible causes? maybe.....
- I have noticed that there is a lean spike about 500-800ms later....might this be part of the cause? That spike seems to be an overly active STFT.
- Hanging on to 2nd gear too long? happens at 12 minutes into the log attached. Tune is also attached.
- torque model being off? I have updated it, calculated coefficients and such, then flashed the cal to both ECM and TCM. the model doesnt seem to be drasticly different than previous

'14 L77, e38, 6L80e, DoD delete, stock rec port heads
BTR PDS stg 2 cam with 122+6 LSA
dual 90mm DBW throttles
6-71 PDS
headers

open to suggestions...

[hjtrbo]

There is only 1 thing that I can suggest. Failing that, hope someone else can help.

Copy this to table ECM 12123 (Throttle follower torque)

N m 200 400 600 800 1000 1200 1600 2000 2500 3000 3500 4000 4500 5000 6000 7000 8000 rpm
1st Gear 120 126.75 133.25 140 35.75 2.75 2.75 0 0 0 0 0 0 0 0 0 0
2nd Gear 120 126.75 133.25 140 35.75 2.75 2.75 0 0 0 0 0 0 0 0 0 0
3rd Gear 120 126.75 133.25 140 35.75 2.75 2.75 0 0 0 0 0 0 0 0 0 0
4th Gear 120 126.75 133.25 140 35.75 2.75 2.75 0 0 0 0 0 0 0 0 0 0
5th Gear 120 126.75 133.25 140 35.75 2.75 2.75 0 0 0 0 0 0 0 0 0 0
6th Gear 120 126.75 133.25 140 35.75 2.75 2.75 0 0 0 0 0 0 0 0 0 0
Neutral 120 110 100 90 20.5 -8 -11 -13.5 -16.25 -19 -21.75 -24.5 -27 -27 -27 -27 -27
Park 120 126.75 133.25 140 35.75 2.75 2.75 0 0 0 0 0 0 0 0 0 0
Reverse 120 110 100 90 20.5 -8 -11 -13.5 -16.25 -19 -21.75 -24.5 -27 -27 -27 -27 -27