He's Too Sexy for His Fat - S2-E17
Revealing mistake: During the scene when the people at the pool think Chris is a car sitting on the diving board, just before Lois moves out of the shot before the scene changes, her lips disappear for a split second. It's really fast but still easy to notice even without pausing or slow motion.
Continuity mistake: In the flashback when Peter fights Ernie the Giant Chicken, Peter gets knocked off the top of an eighteen wheeler and grabs the second rung at the bottom of the truck's ladder. But when the truck driver sees the pair in his side view mirror, Peter is hanging off the top of the ladder. (00:02:00)
Continuity mistake: Osama bin Laden's dialysis machine disappears after Stewie knocks him down. (00:02:30)
Continuity mistake: After Joe shoots a hole in the table, the hole changes size. (00:02:00)
Continuity mistake: When the Griffins are driving to Washington we see a faraway shot of the car driving from left to right. Peter and Lois are in the front and Chris is leaning back on the back seat. In the next shot, Chris is leaning forward against the back of Peter and Lois's seats. (00:19:30)
Continuity mistake: When Peter says he's gonna buy his family the biggest meal they've ever had, Stewie's eyes are drastically bigger than usual. (00:13:15)
A Very Special Family Guy Freakin' Christmas - S3-E16
Continuity mistake: When Peter is driving, Quagmire is sitting beside him and Cleveland and Joe are in the back seat. Joe has brown hair and he's wearing a gray knit hat and a light coat with a gray fur collar. When Quagmire is sticking his body out of the car door and yelling "Whooooooa! Whoooooooa!", look at "Joe" in the back seat. Joe doesn't look like Joe in this shot. He's wearing a Santa hat and a brown coat just like Quagmire's, and a bit of his hair is also black like Quagmire's, instead of brown. (00:05:30)
Family Guy Viewer Mail #1 - S3-E21
Continuity mistake: When Lois picks up the fridge there is nothing stuck to the fridge but when she puts it down there is a note stuck to it. (00:09:40)
Continuity mistake: When Ulysses S. "Griffin" is chugging beer with Robert E. Lee, Ulysses wins. When he says "How's that Robert E. Lee," he puts the beer glass on his head. After Robert says, "Okay no more slaves, but we still don't have to read books," the glass is in Ulysses' hand. In the next shot it's on his head again. (00:10:05)
The Cleveland-Loretta Quagmire - S4-E5
Other mistake: When Peter is painting the Sistine chapel, he has green paint on his brush, even though the picture is entirely black and white. (00:03:50)
Chitty Chitty Death Bang - S1-E3
Continuity mistake: When Meg introduces Jennifer to Lois, she is, as usual, wearing her glasses. However, right when Jennifer says, "Bye Meg," Meg is seen in the shot, and her glasses have disappeared. Her glasses are back on in the next shot.
Continuity mistake: When Chris is saying "I'm not supposed to tell Mom cos she'll just bitch about it" there is a door behind Lois with a box next to it. In the next shot there is a smaller box next to that box which was not there before. (00:09:00)
Continuity mistake: After Lois accuses Stewie of peeing on the carpet, he asks her to bend down and slaps her with a glove. The glove remains in his hand in that cut, is still there when there is a wide shot of Peter, Stewie, Lois and Brian (you can just see it next to his trousers in his hand), but when it cuts back to Stewie and he starts on about "the outrages" etc, it is gone (the cut is instant, no time for him to put it back in his pocket). A common error, this one just struck me as strange, because the sandwich Stewie threw at Lois is there the entire scene. (00:03:35)
Peter, Peter, Caviar Eater - S2-E1
Continuity mistake: In the scene where Lois goes down to the room where Peter is dancing, Peter is wearing blue pants. After he walks over to the door and greets her, he still has blue pants. The next shot of Lois and Peter dancing has him wearing his normal green pants, but after that it goes back to blue pants for the rest of the scene. (00:11:35)
I Never Met the Dead Man - S1-E2
Continuity mistake: The family visits Peter in the hospital. In the long shot, there is nothing on Stewie's head. In the next close up, a band-aid appears on his head. (00:20:30)
Mr. Griffin Goes to Washington - S3-E3
Continuity mistake: In the scene where Peter is at the baseball game, Stewie is sitting next to a boy he calls "Opie." The camera then cuts away to a clip. When the camera cuts back, "Opie" is gone and a grown man is now sitting next to Stewie. (00:02:55)
Continuity mistake: When Meg is putting down traps for Joe, she puts down a lot. Then when the Griffens leave and the giant rat comes, there are only a few. Then when Joe says "bring it on," there are a lot again. (00:11:00)
Continuity mistake: When Peter is talking about how annoying it is to be locked up in the house, Brian disappears from the couch in quite a few shots. (00:07:50)
The Courtship of Stewie's Father - S4-E16
Continuity mistake: When the baseball crashes through Herbert's window, the glass shards are in different places in different shots. (00:04:05)
Peter, Peter, Caviar Eater - S2-E1
Continuity mistake: In the scene where the Griffins are at the yacht club, Peter is telling a rat story. Before he talks about a steak, Lois' earrings are white, but right after they suddenly change to blue. (00:09:10)