2014 Automatic Scion FRS 83K miles.
My car's RPM dips when I brake with medium effort. My idle RPM is ~750 but when I brake, it drops down to around ~550. Because of this, the headlights flicker.
Now hear me out, this ONLY happens when the car is warmed up and when I brake in drive. When I just let the car coast to a stop, it doesn't happen until I brake. When I switch the gear to neutral and brake, it does not happen. When the car is cold (first 10 minutes of starting my car in the morning) it does not happen. It ONLY happens when the car is warm and in drive.
What the hell does this problem sound like? Could auto trans fluid change fix this? Could it be a dying battery? I don't have a problem with starting my car in the cold (~15 fahrenheit).
No CEL's. No TSB's.
I'm lost and any help or ideas of what it could be would help.
Small log of just the idle drop:
https://datazap.me/u/nancyle/rpm-drop
Longer log of regular driving:
https://datazap.me/u/nancyle/longer-drive