Continuity mistake: When young Al reaches forward with his left arm to take the book that Miss Degroot wants to give to him, she quickly pulls back but young AL still has his arm raised. In the next shot, his hand his down by his side.
Can't Dance, Don't Ask Me (aka Kelly's Dance) - S3-E13
Continuity mistake: During Kelly's dance, a nerdy girl grabs Bud and starts kissing him, but in the next shot, Bud is standing alone in the background. (00:20:30)
Can't Dance, Don't Ask Me (aka Kelly's Dance) - S3-E13
Continuity mistake: While Kelly is dancing with the guy at school, a nerd girl starts kissing on Bud and pushes him backwards. The very next second when the scene changes, Bud on the left side is back playing the record for the music without anyone around him.
I'll See You in Court - S3-E10
Continuity mistake: While they are in court, Steve is talking about the case and the clock says 12:30. Next time he's seen and talking about privacy to the jury, the clock says 11:30. Then when done talking, the clock says 3:00. The very next scene as the court proceedings are going forward, now the clock says 12:29. Next scene says 4:32. Than backwards again. The clock is moving forward and backwards throughout the entire scene.
Answer: It was one of the hoses connected to the engine, nothing specific, but to indicate that Al tampered with the vehicle.