If you realize this within a few seconds after you started typing you could close it and it should ask if you want to save the changes. Just say no at it will save the original (or what ever it was up to the last autosave...)

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95 E300D gave away
77 300D, 227k, station car
83 300CD 370k, body gone away to the rust gods, engine is in a Yota pickup, going strong
89 190E 2.6- 335k, no more
79 VW FI Bus- 154k summer driver
59 VW Beetle ragtop- 175k
12 VW Jetta- 250k
74 MG Midget-78k