any update on this OP?

having almost the exact same issues....

2013 BRZ 81k miles

only mod is a mishimoto intake tube and k&n drop in that have been on for 40k with no issues. This just started today out of the blue at a stop light, noticed rough idle, hopped on highway with no issues at all, car felt completely normal.

getting off the highway the rough idle started again and the CEL came on, threw on my obd2 scanner and pulled codes p219a and p0302. Got home, cleaned the filter, and cleaned the MAF, reinstalled cleared codes and test drove, after about 15 miles same codes came back.

Dont know where to start diagnosing.....

Nope I never fixed it. Swapped the motor out.. Did you ever get anywhere?

Reviving an old thread because I'm having exact same issues and they seem unresolved.

Same issue here with my 14 BRZ. Misfires will accumulate on cylinder 2 like crazy. After driving awhile, then coming to a stop and idling it will start misfiring like crazy. Sometimes suddenly a change and it smoothes out and no misfires for the remainder of the drive.
Tried replacing spark plug, coil pack, direct injector. Nothing solves it. Have not looked at the hpfp pressures though......

I'm having the same issues as well as my ltft is up around 14%-22%. They're also pulling the same codes as Ravi's car. I'm starting to believe that the valves need to be adjusted.

Most common caise of high positive fuel trims at low rpm is intake or exhaust leaks.

My tuner made my tune richer to counter the vacuum leak, to the point where my fuel trims are -20% when driving. What kind of damages am I looking at long term?

Best get vaccuum leak fixed then get tuner to fix up tune

Still having the same issues, just wondering if the motor has to come out for valve adjustment