Plot hole: Brian bets Stewie about being at high school for a week. However, this was before Peter's stroke, and before the fire at McBurgertown. It would take at least a few weeks for McBurgertown was rebuilt, then Peter had his stroke, and then Lois tells Chris Peter's stroke was 3 months ago. After this scene, Stewie tells Brian he has lost the bet. However, the bet would only last one week.
Continuity mistake: When Muriel Goldman dies, everyone gathers up around her. When that happens, you can see Tom Tacker and Meg in the background, although they both disappeared a few scenes earlier. And than when everyone gathers downstairs, they do a body count and discover Tom and Meg are missing and only then are they found.
Continuity mistake: Just before the pest control team leaves for the Griffins', we see the black team member holding a shotgun in his hand. After showing Logan in shot, it returns to the black member and he's now holding what looks to be an MP5 machine gun. In the following shot as he starts to slide down the pole, the gun is once again a shotgun.
Continuity mistake: When Derek Wilcox is killed and on the ground, he is on his front with his head turned. He got hit above his right eye and blood is coming from underneath him, but after everyone else arrives outside, he is on his back with the wound above his left eye and blood is all over his face.
Continuity mistake: When we first see the sign outside the Quahog institute of performing arts, it has a cartoon take on the comedy and tragedy masks in the corners. In the left hand corner is a black mask with big ears and a smile and on the right is a white mask with a frown. Later on, the black mask has the frown and the white mask has the big ears and smile and the 3rd time you see the sign it has changed back again.
Continuity mistake: When Peter and Brian are escaping from the locals in their car, they go over a ridge. They freeze in midair and a voice says "those Griffin boys..." and the screen goes black. Then, in the next shot, the whole landscape is different. Even though the angle of the shot is different, that doesn't account for the disappearance of Chris and Sam or the colour-change of the sky. (00:14:40)
Plot hole: When it is revealed that Chris's teacher was never born, Teacher Doug introduces himself, despite the fact that if Chris's teacher was never born, Doug would already have been teacher for the entire year, and therefore all of the students should know him and he would not have to introduce himself.
Continuity mistake: After Conway Twitty finishes his song, the scene cuts back to Perter and his family at the kitchen table. Take notice that Lois is sitting next to the back door, and Brian is sitting next to the kitchen sink and window. Keep an eye on that kitchen sink, window and door, because it will be replaced by a yellow wall with the telephone now being closer to Lois. Later as Lois, Brian and Peter are discussing OJ Simpson, the sink, widow and door return.