When Michael finds out that K.I.T.T. has been completely dismantled, there are boxes which hold most of his parts. You can see a normal car steering wheel sticking out on the top box. K.I.T.T. never had a steering wheel; he had a steering yoke.
When Devon, Michael and Russell are talking in front of the box containing KITT's dismantled parts, Russell's left hand is clearly leaning on an adjacent rail. In the next scene, as he says "the car didn't exactly have fresh oil on the dipstick", both his hands are suddenly in the air.
When Michael finds out that K.I.T.T. has been completely dismantled, an analogue dial tachometer is clearly visible in the box containing his parts. K.I.T.T. never had any analogue dials - his dashboard was completely digital.
When the car is sinking KITT says the Chevy interior is airtight, this can't be true if the car was airtight then it would not be usable because the driver would run out of oxygen after driving twenty-five minutes or always drive with the windows down.
A man fires a rocket launcher from the back of a van. Since a man-portable rocket launcher uses a rear aperture to vent the exhaust from the rocket to reduce recoil, the backblast from one should kill or incapacitate anyone within the van.
Most (if not all) the police cars in the movie are Chevrolet Berettas. In the scene where the police are chasing the decoy van that is believed to be hauling the guns, the police cars are clearly Chevrolet Berettas. However, when the villains open the back of the decoy van and fire a missile at the lead police car, the target police car suddenly changes to a Dodge Daytona upon impact of the missile. This can be clearly seen with the differences in wheels and headlights in the clips following the explosion (the car on fire has two headlight sections, whereas the Beretta has one).
Shawn is shot in the left shoulder but later in the chase in the mall she is holding a gun with both her hands at Watts this is not possible to do when a person is shot.
When Officer McCormick is being brought into the hospital, the sound of vital sign monitors can be heard, in spite of there being none present.
When KiTT was retro fitted into the dash of the Chevy, the voice module is fitted upside down to how it would of been fitted in the Trans-am.
Michael has fitted KITT's microprocessor unit in his 1950s Chevy. When the camera pans from Michael in the driver's seat to the scanner in the grille, a crew member can be seen reflected in the chrome.
Ms. McCormick's memories as retrieved by both K.I.T.T. and Dr. Glassman are in the third person. Considering that they are her memories, they should be in the first person.