I Never Met the Dead Man - S1-E2
Continuity mistake: When Peter is explaining to Meg about "bribes" in one shot the window in the kitchen door disappears. (00:09:00)
Continuity mistake: Just before Peter enters the tunnel in his new car, the white line in the middle of the road is blotchy and not continuous. When the shot changes to Peter's POV, the line has completely disappeared. The next shot which shows the car side on, there is now a straight white line on the road. (00:14:20)
Other mistake: When Peter is dancing to his musical number on top of the table, his head continually shrinks until the end of the shot, where his head is around a third of what it was originally.
One If By Clam, Two If By Sea - S3-E4
Continuity mistake: After Peter has been to the newly opened bar, he runs to his house door (which is red) and when he opens it, the colour has changed to brown.
Continuity mistake: During the Star Wars rip-off at the end, just before Peter climbs the Town Hall stairs, the people on the sidelines change. (00:19:45)
Peter Griffin: Husband, Father...Brother? - S3-E14
Continuity mistake: When Stewie jumps on the picnic table and begins his dance, at one point he undoes his coveralls and removes his shirt. In the next shot he is fully clothed.
Factual error: When Stewie is playing Simon Says, the sequence Stewie plays is different than the one that the Simon Says played. If he played it wrong, there should have been a sound from the Simon Says indicating that Stewie played it wrong.
Chick Cancer - S5-E7
Continuity mistake: Just before Peter announces his decision to make a chick flick, the tissues on his lap change position.
Continuity mistake: When meg is at the car with the girl and the two boys, the guy on the right has the Q and a basketball above it. In the next shot the basketball becomes white. (00:12:17)
I Never Met the Dead Man - S1-E2
Continuity mistake: When Peter crashes into the cable tower in the far shot, the number plate isn't there. Yet in the close up shots it is there. (00:06:05)
Continuity mistake: At the football game, the row of people behind the Griffins disappear in one shot, and reappear in the next, with not enough time for them to have all moved away, and all moved back. (00:07:10)
Continuity mistake: When the government people are looking at the missiles spelling 'Happy New Year', the 'Y' in 'Year' changes distinctly between shots. (00:06:50)
Peter, Peter, Caviar Eater - S2-E1
Continuity mistake: In the scene where Lois and Peter are at the historical auction, when Lois stops to talk to her friend the person standing next to her friend is wearing a green suit. In the very next shot he is wearing a black suit and vest.
Peterotica - S4-E24
Continuity mistake: After the Quahog Creek clip is over, they show a picture of the house. In the background there is a tall silver building that wasn't there the last time they showed a shot of the house. (00:17:45)
There's Something About Paulie - S2-E16
Continuity mistake: When Lois asks to speak to Peter in the other room after sitting down for supper with Paulie, the door they come out of is where the front door is all the time, not the kitchen.
Airport '07 - S5-E12
Continuity mistake: When Peter unplugs the plane's fuel hose, he spills fuel near the stairs, but when the two airport workers come over, the spilled fuel is gone. (00:05:05)
Peter, Peter, Caviar Eater - S2-E1
Continuity mistake: Just after Peter sings "Tonight I sleep alone", his position in relation to Lois drastically changes. (00:07:00)
Continuity mistake: When Stewie has chicken pox the red marks on his face change position many times between shots. A noticeable one is just as he is saying "No, damn you, I've got to finish what I started".
Mr. Griffin Goes to Washington - S3-E3
Continuity mistake: When Mr. Weed is crying about losing his job, we see a view of a long line of trees in the window behind him. The camera switches to a close-up of Peter. When it zooms out again, the trees on the right of Mr. Weed are missing.
Suggested correction: I watched this part of the episode twice and no trees are missing in the window behind Mr. Weed after the close-up on Peter. Actually, Mr. Weed's head is covering part of the window where you can't see the trees on the right when he's lying on the table, but when he gets up you can see all the trees.