Help a gal out?

[holmes221b]

I remember promising to write an AU on jim_and_bones that involved me using my knowledge of cars. Unfortunately, I neglected to add that post to my memories so that I would be able to link to it once the story was finished (it's not finished yet by the way, I just started writing it last night). Anyone happen to remember which one it was?
It wasn't August 2, 2011, I've checked that one already and it's not the one (though I could have sworn that it involved that particular picture of Karl).