DSlater hit it on the mark, it is the door strikers. If you take a look, the cube on the doorframe has a piece that protrudes a bit. Mine is tan-colored plastic on the SD, not rubber. I was able to wad up a bit of duct tape and stick it on the striker and it seems to work okay--not pretty, but functional.

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TC
Current stable:
- 2004 Mazda RALLYWANKEL
- 2007 Saturn sky redline
- 2004 Explorer...under surgery.

Past: 135i, GTI, 300E, 300SD, 300SD, Stealth