There are two cars used in the Lamborghini scene. The first one in which Jim drives up is, in fact, a Lamborghini, but the car that gets destroyed by Herbie moments later, is a red Jaguar.
Jim tries to make Herbie stop by shutting off the ignition, but it's stuck; the ignition key is already in the off position.
When Tennessee is hanging out of Herbie over a cliff, the number 53 is missing from Herbie's passenger door.
When Tennessee finishes welding Herbie, the view out the back window shows the scenery traveling sideways, but in the next scene it's going straight again.
After Herbie hits Mr. Wu's shop he has a dent up front, but later in the impound lot this dent has gone and his headlights have no glass in them.
When Jim first buys Herbie, he drives him from a single lane street onto a two lane street and past a sign that says "Left lane must turn left". Jim has just entered a one way street going the wrong way.
The Volkswagen was not being pulled behind the cable car. It was actually driven from the back seat by a man whose head can be briefly seen in the right rear side of the car.
In the final scene Thorndyke and Havershaw are working for Wu and start spraying each other with lubricant, but the lubricant is black. No new lubricants are black - only used oils become black.
As Herbie took off from the starting line in Virginia City, it's clearly seen that this is a sped-up camera effect.
During the El Dorado race, Jim wears a blue helmet and is the designated driver of Herbie. However, when Herbie crosses the finish line at the end of the first leg, riding on a wagon wheel, the person in the driver's seat is wearing a white helmet.
When Herbie gets scared to get on the freeway there is a sign showing Findlay, Garfield, Wilcox exits. This is in Los Angeles, not San Francisco where the film is set.
All of the scenes in the Riverside raceway or actually shot in Laguna Seca.
The drawn up map during the driver and owner meeting as a lot of geographical errors when comparing them to the actual locations. The starting line supposedly is by the Ahwahnee Hotel which is in Yosemite Valley, but the other locations (such as Chinese Camp and other places) aren't really on the route of the race. The layout for the race also is nowhere near Virginia City (which is only 70 Miles Northeast of Lake Tahoe).
The El Dorado (supposedly a local racing contest) is nationally televised.