Audio problem: Lorraine comes to see Marty in Doc's garage in 1955 to ask him if he will go to the dance with her. Just before Lorraine moves to the other side of the car from where she walked in, she begins to say something to Marty. The problem is that her lips don't move when she talks, I guess the right clip ended up on the editing room floor. (01:11:40)
Audio problem: When Miguel and Steele are collecting some more of the zombies, Steele says 'Nice hat, asshole,' and laughs. Watch carefully at the end bit: they dubbed a laugh into the movie, but it's painfully obvious that his mouth doesn't move as he does it.
Audio problem: When Ben and the rest of his friends are "out on the town", he starts his car to go home, but when he does it makes the distinct sound of an older Chrysler when he was driving a Cadillac.
Audio problem: When Master is riding on Max's truck, he says "Everybody, have a good time! Saturday night!" His mouth doesn't match up with the words.
Audio problem: At the 'punk' club in Chinatown, the live singer (or yeller) is lip-syncing (and with lots of lips but very little of the synching). (00:38:10)
Audio problem: Howe kills the two guys on the sailboat with an M-16, but the sound is of an Uzi.
Audio problem: At the bar when they're leaving, Anthony Michael Hall's mouth doesn't match up to anything being said.