5.7 Hemi going lean when coming to a complete stop

[jgeiger]

Hey guys, i have an issue we've been fighting for a while with limited and unpredictable success. Have searched the internet high and low with no luck.
2005 Dodge magnum 5.7-based stroker motor. When loading a new tune on, everything is hunky-dory for a week or two, but as the adaptives begin to settle in(my best guess), I get an increasingly severe lean spike when coming to a complete stop in gear(also a lean spike when thrown into neutral, but less concerned about this).
Walk through of how it happens:
1) Drive car
2) Come to a complete stop. Stop sign, stop light, etc (auto trans)
3) AFR spikes to 17.5-19.0, RPMs drop, vehicle almost dies
4) Car corrects itself, RPMs come back up, bounce down to normal idle. (May happen a few times depending how bad it is)
5) AFR slowly comes back down to stoich - usually within 20 seconds.
Not sure if any of you guys have ever seen this before, or what the cure may be. Vehicle has been checked multiple times for vacuum and exhaust leaks. Naturally Aspirated. No pending or permanent codes. I can only assume it is tune-related, as every time a new tune is loaded(and adaptives reset), the problem goes away completely, then gradually reappears over the next couple weeks as the adaptives set back in.
Thank you everyone.

[mikel]

Have you logged it and asked your tuner to look it over?

[jgeiger]

Yes, Johan has been my tuner from the beginning, and we attempted to address this concern multiple times last year. I replaced O2 sensors, changed cam and heads and intake, and we restarted this year from scratch. We are on our second revision of this years tune, and the problem is arising again. i am sending him another datalog tonight, with this concern voiced.

[mikel]

Really not sure here.
if its an early 05 PCM/cal it may be worth it to go to a later 05/06 style PCM and cal to see if that helps?