Continuity mistake: The age difference between Chris, Meg and Stewie keeps changing throughout the series. At the beginning of the series, Chris is 13, Meg is 15 and Stewie is 1 (he is after S1 E3 Chitty Chitty Death Bang). In series 4, Chris then goes to high school so he must be 14 by that time. It isn't referenced that Meg has aged between series 1 and series 5 until S5 E10 Peter's Two Dads where she turns 17, so she must have turned 16 during the past five seasons. Despite Meg having aged two years throughout the series, Chris remains having only aged one year since S4 (Age 14 referenced in S9 E13 Trading Places). Then in S10 E10 Meg & Quagmire, Meg then turns 18, and still Chris hasn't aged. Also, Stewie remains one year old after all of Chris and Meg's birthdays. If it were consistent, Meg would be now 18, Chris would now be 16 (not 14) and Stewie would now be 4 (not 1).
Continuity mistake: In the episode with Peter dating a girl with a black hand, in one scene, we see Peter with the girl. After Peter leaves in the 3rd shot, the black on her right hand now appears on her left hand.
Continuity mistake: When Meg is looking through her magazine in one shot there are just some adverts, but in the next shot there is a full page picture of someone. (00:01:20)
Continuity mistake: During the breakfast scene when Peter is lying on the table, the food on the plates changes positions between shots. (00:04:45)
Continuity mistake: When Stewie is acting like a ninja to get his gun back it is in a cupboard with 2 shelves. Yet when the gun is lifting him up there's only one. (00:09:40)
Continuity mistake: Stewie tries to get his mind control device back from the kitchen. The cupboard door is open when he falls. In the very next shot, Lois turns the light on in the kitchen, and we see the door has closed without anyone touching it. It is open again after that. (00:09:50)
Continuity mistake: Brian's newspaper's name changes from "Daily Informant" to "Daily Tim...". The newspaper also turns upside down between the two shots. (00:11:15)
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)
Continuity mistake: When Lois is outside, the mail lady gives her Peter's check. The front door has no window on the outside, yet inside there is one. (00:14:25)
Continuity mistake: The welfare cheque that Lois gets from the postal worker is addressed: 'Peter Griffin, 72 Spooner St, Quahog, RI' but the Griffins live at 31 Spooner St. every other time their address is mentioned. (00:14:26)
Continuity mistake: When we first see the two commentators in the box, the blue suited one doesn't have a mug, but in the next shot, there is a mug next to his microphone. (00:15:35)
Continuity mistake: When Lois, Meg, Chris and Stewie first enter the courtroom there is a brown-shirted man sitting next to Quagmire. In the next shot, there is a pink-shirted man there. (00:18:25)
Continuity mistake: When Peter is testifying in court, the microphone on the witness stand disappears in the shots from the judge's point of view. (00:18:43)
Continuity mistake: In the first shot of the flashback showing the family watching "Philadelphia," Peter's eyes are about twice as big as they normally are due to the Irish coffee, but are instantly back to normal in the next shot.
Continuity mistake: During the flash back at the ice cream store Peter's eyes change in size twice before he licks the ice cream and then one more time after he licks the ice cream before falling down.
Continuity mistake: Stewie's overalls are missing during one of the shots of the Griffins at court.
Continuity mistake: When Lois enters the kitchen while talking about needing the checkbook, her shoes aren't exposing her feet like they usually do.
Continuity mistake: When Peter winks at the camera wearing an afro, it is black, but when he sits back down, the afro is brown.
I Never Met the Dead Man - S1-E2
Continuity mistake: When Lois is feeding Stewie broccoli at the beginning in one shot the plate disappears from his table, and then in the next shot it is there with a fork next to it. (00:01:35)
I Never Met the Dead Man - S1-E2
Continuity mistake: At the stop light, Meg starts racing a guy on a horse drawn carriage. When they leave the light, they are going down a road by a cliff side, and suddenly there are no lines in the road from the side angle. When it cuts to the carriage's wheel coming off, suddenly there is a dotted yellow line in the road by it. (00:03:17)
