I did a search and came up empty on this one. On my 2011 SHO I am getting a recurring P0442 Small Evap Leak CEL code. The SHO seems to run fine and has no other codes showing up. I had some work done and it was gone for a while and it has returned. I've already replaced the tube under the hood for the purge valve and my next step is the valve/solenoid at the charcoal cannister. I am beginning to suspect that it's the fuel filler flap thingy as it seems to return after fueling (I do make sure that the fuel door is completely clicked shut). I've already tried to clean the flap thing with the filler funnel (as shown by Fordtechmakuloco).
Has anyone replaced the filler flap thing and if so, how big of a project is it? I suspect that the part is the whole neck and tube to the tank and not just the top end flap. I am open to any hints or suggestions if the charcoal cannister solenoid/valve doesn't do the trick.