after fooling around a bit and several corrupted savegames later i managed to track down one savegame corrupting bug, which happens only AFTER you loot the "Reverse Pulse Cleaner"-Item and leave Motor-runners "room".
oh btw. sorry for my hopefully not-so-bad englisch, because i'm no native englisch speaker. =)
edit* wops, i forgot to mention that it is in vault 3 and that every save after looting this item is corrupted