Peggy Loves Al, Yeah Yeah, Yeah - S2-E17
Other mistake: When Bud goes upstairs with his fake bag of "Valentines" (actually a bag filled with bottles), Kelly begins to look through some from her bag. Behind her, you can see David Faustino (Bud) purposely moving slowly up the stairs because Christina Applegate (Kelly) is about to find the envelope that is addressed to Bud.
Just Married ... With Children - S2-E20
Other mistake: Al gets sat on by 3 heavy women. The scale says 927 pounds. 4 more women sit down and the scale says 1071. So 4 more heavy women only added 144 pounds? Impossible.
Just Married ... With Children - S2-E20
Other mistake: Al and Peg win a new Mustang in this episode. It's never seen again.
Answer: It was one of the hoses connected to the engine, nothing specific, but to indicate that Al tampered with the vehicle.