evap purge causing misfire
 

so i've had a problem for a long time that nobody has seemed to have any idea about wherever i ask. i've managed to narrow it down finally! hoping someone can give me a bit more insight to figure out exactly which component is faulty.

problem: when i fill the gas tank, i get cyl. 1 misfire. normally at idle.

cause: seems to happen when the PCSV purges the gas tank pressure to the intake. also had P0441 at the same time. disconnect the PCSV to block off the evap from purging to intake, and voila problem gone. not an ideal solution however.

after testing it, i can say the PCSV is fine. so for now my theory is this: i have an air leak somewhere between the tank and the PCSV. this could include the charcoal canister. air intake leans out the mixture and boom misfire.

any ideas? anything i've missed here?