When Michael and KITT use the turbo boost to jump over the car on the highway, there is almost no distance between the two cars. However, in the next shot there is more than a car distance between them before the jump takes place.
After Michael meets with Dr. Thorpe and has KITT scan the gun from Dr. Thorpe's truck, Michael hears Maxine's call for help and Michael takes off running and calls for KITT; when KITT spins around you can see a hand turning the steering wheel.
On the highway, when KITT the car goes ahead of the pick-up truck in order to slow it down, as it applies the brakes, a closeup shot shows a wheel on the truck stalled and skidding when in fact it should have been one of KITT wheels, since the truck was actually accelerating instead of braking.
Despite the ruckus heard while Tommy Lee is trying to take the horse away from the vets' barn, there is no accompanying movement of the horse trailer he is supposedly held in.
Obvious stuntman when Michael climbs out of the car's trunk onto KITT's hood.