OK, I may be missing something here. There's the plastic gas gap which has a few moving
parts and screws into the filler tube hole. Then, there's the metal door attached to the chassis
that's released by the pull lever. I don't remember any plastic piece on the metal door.
This piece sits between the metal door and the gas cap? If you're saying part of the gas
cap is stuck I'd just buy a new one. Must've missed something.
It's the metal cap attached to the body, but mine's actually plastic. Sorry for being confusing. It won't stay shut, and though I have a release lever inside the car and can't really even see any moving parts inside that would make the release lever operate.