Corrected entry: Hank, Dale, Bill, and Boomhauer talk about the fun they had in Cotton's Cadillac when they were kids. However, in the season 5 episode "When Cottom Comes Marching Home", Lane Pratley comes to take the Cadillac away because Cotton is a few months behind on payments. This means that Cotton couldn't have had the car since Hank and the other guys were kids. Lane Pratley is around Hank's age, so he wouldn't have sold Cotton a car back then.
King of the Hill (1997)
1 corrected entry in season 11
Starring: Brittany Murphy, Pamela Adlon, Mike Judge, Kathy Najimy, Johnny Hardwick
It's Not Easy Being Green - S5-E16
Factual error: Boomhauer's car, Ms. Sally, has a Texas flag license plate on it. These plates were not issued until 1992, but Ms. Sally was driven into the quarry in the late 70's or early 80's.
Hank: Calm down, Boomhauer! I can't understand a word you're saying.
The Wedding of Bobby Hill - S3-E14
Trivia: During Hanks's conversation with Bobby when he tells him that he will have to marry Luanne, look at the shelf behind Bobby. There is a Bart Simpson doll there. A few years before this was featured the Hill family was in the crowd at one of the pee wee football games in the Simpsons episode "Bart Star".
The Man Who Shot Kane Skretteberg - S2-E7
Question: When we first meet Kane Skretteberg, what is the song he and his band are playing in the garage? It is right before they start singing Funcenter over and over.
Answer: If you are talking about the "Thou shalt not do this, thou shalt not do that" song, I'm not sure if a song like that actually exists. Green Day, the guest voices on the episode, might have just been improvising to keep their appearance from being too obvious.
Correction: In the season 3 episode "Nine Pretty Darn Angry Men", Lane Pratley stated "I own Pratley Ford, Pratley Honda and I got my eye on Pratley Cadillac- my daddy ain't doin' so good". Presumably the elder Pratley sold Cotton the Cadillac before his son bought his Cadillac dealership.