So I have been working with a reputable tuner and my problem does not seem to be tune related but it did occur while tuning. Figured I would ask here in case anybody has a suggestion.

I have no CEL (check engine light).
My cruise light is constantly flashing.
My idle remains around 1000 rpm but when driving and stopping when warmed up idle will bounce down to the bottom of the tach and then back up over 1000 rpm. Almost stalls out.
vacuum is stable in the car around 20 psi except when idle is fluctuating.
06 WRX donor with a lot of modifications.
Car ran perfect all weekend and then Monday this started.

Any ideas?