At the beginning of the chase scene, the red Ford Falcon's license number is "LXI 483". In the close-up of the car being struck by bullets, the number is "QLW 940".
After Reed and Malloy turn onto a dirt road when trying to head off the horseback rider, the close-up shows a smooth paved road out the rear window.
Tires don't squeal when a vehicle is turning or skidding to a stop on dirt, as they did when Adam-12 approached the horse thief.
The explosion at the front of the red Ford Falcon happens just before the car appears to hit the tree. The car never actually hit the tree, it just comes to rest next to the tree. The camera angle puts it behind the tree and there are no marks on the tree.
After Leroy is apprehended following the theft of the horse, he tells Reed and Malloy that he's from Big Springs, Texas. There is no such place - he should have said "Big Spring".
Susan claims to be either 17 or 18 years old, yet Jo Ann Harris was 19, almost 20, when this episode aired.