Character mistake: When Bud is showing Al his school project of a fan page turner, he has it on the left side and blowing the pages left to right. That would be blowing the pages the wrong direction to flip pages. It should be on the right side changing pages right to left.
The Chicago Wine Party - S7-E7
Character mistake: Throughout the entire episode, they talk about the beer tax being 2 cents. At the very end when Terry is doing her on air broadcast, she calls the tax a "2%" tax. There is a big difference.
Answer: It was one of the hoses connected to the engine, nothing specific, but to indicate that Al tampered with the vehicle.