After K.I.T.T. is sent tumbling down the bank, his roof is flattened down quite a bit, and other damage is visible to his front end. Yet after he turbo-boosts out of the gravel-pile, his roof and body are undamaged.
When Michael is looking around the desert where Frank's tractor was stolen, he is wearing white. In the wide shot of him driving KITT in the very next scene he is wearing black, but in the close-up he is wearing white again.
Moments before KITT is pushed into the quarry, both driver and passenger side windows are open. When the car rolls down the hill, they are closed.
When KITT sprays his oil onto the road he releases two streams. When the two cars stop, there is now a wide swathe of oil on the road, much more than was released.
Michael brings up K.I.T.T.'s Trajectory Guide as "new", despite the fact that it was first seen in "Blind Spot".
This is because "Big Iron" was filmed before "Blind Spot".
This is because "Big Iron" was filmed before "Blind Spot".
When K.I.T.T. releases the oil slick the license plate is reversed.
When K.I.T.T. is pushed down the hill into the quarry, there is a mannequin in the driver's seat.
When Michael and KITT are about to be buried under tons of gravel, some shots show that the car is a Pontiac Trans Am, rather than the concept car used in the series.
After Michael speaks with KITT in the sandy area KITT says that he scanned and found some cactus. When Michael drives away it's the script paper is seen taped at the screens inside at the dashboard.
In Tulley's one of the arcade sound effects is from an Intellivision game called 'Space Battle' - a game which is not found in arcades.
When KITT and Michael are trapped under the dirt Michael says, "That five minutes will go pretty fast anyway". However, his lips say something else at the beginning of the sentence and the audio has been dubbed over.