Fuel door won't open - not a lock issue

So I've had this issue since I bought the car from the previous owner, and it's annoying me enough that I'd like to fix it. When I go to open the fuel door, I can't simply do the one-touch method to pop it open/closed. It seems to take some pressure at the back of the door and then a good knock toward the center of the door before it pops. It's quite a complicated procedure, and one I'd rather not do every time I fill up. I've looked at the black plastic latch, and it still turns 90° as I push it in, but it doesn't "lock" in the in or out position.

Anyway, has anyone replaced this piece, or does anyone have a manual that might indicate how to replace it? I'm assuming it'll mean going in from the trunk and accessing it from the back side? I'd like to do it myself if possible to save a few bucks.

Mine had the same problem and it was the lock acting up.
The lock was locking uncommanded.
I cleaned the plug to the lock and then my wife said she would rather not take the chance that it would not open and I disconnected the lock and left it off.

Mine locked randomly too and it wouldnt let me in to fuel up, dealer replaced it under warranty. They did go in from the inside.