CEL p0456 on 2013 n/a help!
 

I have a 2013 FRS manual n/a with 50k miles. Stock except for gruppe s cattless header, mxp comp rs exhaust, and oft stage 2 tune(mods have been on for a year with no problem till now)
Just had the p0456 cel pop up for evap system. Tried doing some research and people say the gas cap but mine is tight. I cleared the code to see if it will come back on but as I've been driving it doesn't seem quite as quick as usual, has hesitation when first pushing gas pedal, and runs rough in reverse slow speed.
Any help or tips would be great, I tried looking for loose vacuum lines but can't find where evap system is.

Update: been 2 days since I cleared it and it now came back on. Does anyone have any experience with this issue, or any advice they can give me? Thanks

check evap canister hoses
check evap hoses under intake manifold have not popped off or cracked loose
check evap purge solenoid connection


use oft to check ltft at idle (over 10% or so) if its high you likely have leak
check idle manifold vacuum should be about -9 psi




https://www.engine-codes.com/p0456_subaru.html

You need techstream to test whether the evap solenoid valves are closing. Sometimes they build up crud and can't seat properly or just shit the bed. I was going to say to go into RomRaider and just disable the CEL since it is just the Evap system.... but P0456 isn't turn-offable.