Revealing mistake: In the scene where Christie Brinkley takes off her clothes and invites Chevy into the pool, he takes off his pants and we are supposed to assume he's naked. When he dives in you can see he's wearing flesh coloured underwear.
Plot hole: When the Griswolds are at Wally World, supposedly the only people there are the guards. Who operates the rides for them?
Suggested correction: The guards also knew how to operate the rides.
Original mistake is correct. There were only 2 guards. 1 they kidnapped. The other they left lying like a dog until he could call the police. Therefore, there was nobody to operate the rides. Besides amusement parks don't train security to operate the rides.
Continuity mistake: After the car is fixed in the desert, the tires all wobble. But when the are leaving the Grand Canyon after Clark steals the money, the tires ride straight again.
Suggested correction: A lot of time passed between that, movies often skip ahead in time, so it can be assumed he fixed the tires at some point in between.
Other mistake: When Clark and the gang force the security guard onto the "screaming meemy" roller coaster, it starts to roll with no-one operating the controls.
Suggested correction: Every ride they ride would be a mistake as there was nobody to operate any of them.
Other mistake: In the first gas station scene, Ellen directs Clark to the gas tank opening which Clark has thus far been unable to locate. Despite being a brand-new car, the inside of the gas tank lid is completely rusted.
Factual error: The whole movie he drives without any valid license plate. Just a crooked colored plate from the auto store. He would have been pulled over for that immediately, and the car probably would be impounded. Then when he does get pulled over for the leash, the cop says nothing about invalid plates. But he asks for registration proof and Clark shows it, even though he has no legal plates. Plus his meaningless plate is crooked, which is also illegal.
Suggested correction: The first 30 days after you purchase a new car you don't need plates.
Any place I've lived has required at least temporary plates before the car is actually registered.
The officer still would have to run the VIN numbers to make sure the car isn't stolen. A long time ago certain states wouldn't give you a temporary plate at all, you would only have the dealership plate on the back of the car which would raise any suspicion of law enforcement if they were to get behind you, but no ticket would be issued as long as the car is within 30 days and not stolen.
Suggested correction: No they show he is never naked, absurd post.