When Andy is eating his hamburger in the diner, Vann is drinking from a glass, the two straws are white when Vann is holding the glass, at one point when the glass is placed on the table the straws are clear. The glass is also repositions itself a few times.
When Vann pulls out in front of Andy who has stolen his car, Andy puts the car into a spin. The shots then alternate between the interior of the car where we can clearly see the windows are either down or clear to an exterior shot where the windows of the car are tinted and closed.
The car's front grill varies inconsistently between damaged and undamaged throughout the movie.
During the car drive, when Andy is showing Vann pictures of his family from his wallet. Andy's seat belt disappears and reappears several times.
When Vann gets out of the car after Andy farts, he clearly closes the car door. However, when he goes to get back in, the door is open.
It's impossible to shift a modern car from "park" into "drive" while revving the engine like Andy did while handcuffed in Vann's car. But on the antique Cadillac shown, there is nothing preventing that action, and it was a common technique used in street racing when cars of that era were popular.
Andy Fiddler is supposed to be a salesman for dental hygienic products and equipment however he has horrible teeth! His bottom teeth are extremely crowded, stained and yellowed. He would not be a very convincing salesman in real life.
When Derrick goes in the house and sees the dead body , he picks up a pen but is not wearing latex gloves. His fingerprints would be on the pen.