Also happens when I hold up the window switches while at a standstill. RPM's will drop a little bit when I hold up the window switches. Is this a sign of a weak battery? Oil light flickers as RPM's drop. I do have a P0171/P117B and P1170 code, but I don't believe that makes the RPM's drop as I brake. I suspect an underlying issue with a battery, which is also causing those codes. My voltages are around 14v though.
2014 Auto FRS. No TSB for RPM drop for my car, as those were for 2015's.
https://streamable.com/rokhr