He's Too Sexy for His Fat - S2-E17
Other mistake: After the cutaway with the lemonade stand not taking credit cards, the episode cuts to an exterior shot of the hotel that the Griffins are now staying in. For a large hotel like that, the parking lot is way too small, showing only two cars in the front with only three visible spots, and one car parked in the street behind the building. Far too few spots and far too few cars considering how many room lights are turned on. (00:05:50)