Continuity mistake: In the beginning, Bart's bedroom's window faces the backyard. When the bus leaves, it faces Evergreen Terrace. At the beginning of Bart's nightmare, it faces the backyard again. (00:00:55 - 00:15:45)
Mr. Lisa Goes to Washington - S3-E2
Continuity mistake: When Lisa approaches the Abe Lincoln statue, there is an old person near her. In the next shot, there are three people suddenly surrounding her. (00:15:05)
Audio problem: When Homer is in the asylum talking in his sleep, his mouth stays open when he's talking.
Continuity mistake: As Homer and Marge are singing in the car, there is one exterior shot of the car, showing it is yellow, but the rest of the scene it is green. (00:05:55)
Continuity mistake: When Homer helps Bart with his racer, the wall of the inside of the garage keeps changing from blue to red. (00:11:45)
Continuity mistake: When Skinner is calmly driving the bus on the way to school, they have obviously gone past a number of power lines (you can see that they have because you can see them in the background). However, when Skinner is trying to get onto the main road, the power lines have disappeared from the background. (00:12:45)
Homer Alone - S3-E15
Deliberate mistake: Arnie says that he drops his bagel. When he does he starts to say it, but when we see the helicopter it has just fallen out. If he dropped it at the time he did, then it would be much further down and wouldn't be visible in that shot. (00:05:20)
Factual error: When Bart is trying to escape from the girls at the start, Bart's door opens into the room. This would mean the hinges would be inside Bart's room and the girls couldn't have been able to remove them.
Radio Bart - S3-E13
Continuity mistake: At the start of the scene where Bart talks to Rod and Todd on the radio, their shirt colors switch. (00:08:50)
Continuity mistake: When Homer laughs at Patty and Selma, for a few frames you can see that the beer can he was holding is gone. It stays beside the phone for the rest of the scene. (00:07:00)
Suggested correction: When Homer is laughing at Patty and Selma he never has the beer can in his hand. He has a drink then the camera cuts to Marge talking about Patty and Selma, Marge then walks out of the shot, and we get a close up of Patty and Selma. The shot then changes to Homer who starts laughing. Enough time to put the can down.
Continuity mistake: There are three mistakes when court is dismissed: 1) the people standing around disappear, 2) the two men with Fat Tony disappear for one shot, and 3) when Bart says that crime doesn't pay, Marge is suddenly standing beside Bart. (00:20:35)
Suggested correction: There are also 3 corrections here. 1) the only people standing near the bench are Lionel Hutz and Seymour Skinner. Seymour is simply out of shot and Hutz is on screen. 2) Legs and Louie don't disappear they remain standing on the steps but due to the camera angle that is now looking across the steps rather than up the steps so they are out of shot. 3) There is a close up of Bart and Fat Tony long enough for Marge to walk over.
Continuity mistake: When Lou and Eddie (the police officers) arrive at the house to take Bart for a drive, their badges are white. When they are driving in the cop car, their badges are yellow. (00:05:30)
Like Father, Like Klown - S3-E6
Continuity mistake: When Reverend Lovejoy gives Bart a t-shirt "Gabbin' about God", Bart puts it behind his back, where it disappears in the blink of an eye. Look closely (pause helps), but it definitely does disappear. (00:13:40)
Continuity mistake: After Lurleen sings 'No-One Understands You', she puts on her apron and picks up a tray. On the tray, there are three bottles of beer. But in the next shot, Homer goes over to Lurleen, and there is only a cup. (00:07:15)
Radio Bart - S3-E13
Continuity mistake: When Homer, Marge and Sting are down the hole and Sting is digging, Homer is wearing a vest. But in the next shot when they find Bart and Homer moves Sting out of the way, he is wearing a shirt. (00:20:50)
Continuity mistake: As Homer and Marge are about to get married, Homer disappears for one shot. (00:10:20)
Burns Verkaufen der Kraftwerk - S3-E11
Continuity mistake: When Horst looks at the pot full of green slime, his mustache disappears for three separate frames. (00:10:00)
Burns Verkaufen der Kraftwerk - S3-E11
Continuity mistake: When Bart starts dreaming what he can do for $5,200, Marge has disappeared from beside him. (00:04:35)
Lisa's Pony - S3-E8
Continuity mistake: Homer's digital watch disappears when he enters the auditorium. It also vanishes in the first shot of Homer in the music store. (00:05:05 - 00:06:25)
Lisa's Pony - S3-E8
Continuity mistake: After Homer watches the tape, Marge suddenly appears beside him. (00:07:30)