When Welther and Smoke are pursuing KITT and Sara in the helicopter, the exterior of the black helicopter is shown three times and each time it is a different helicopter.
While side-slamming into the bad guys' SUV, KITT's left headlight smashes (you can see the metal ring fly off on impact) but it's intact for the rest of the chase. This is before KITT's repair system is turned back on.
In the scene where Mike, Charles and Jen are leaving the hotel, Mike has the ear piece on. When Agent Rivai confronts them, he's no longer wearing it. The scene cuts back and forth showing him from behind/her from the front wearing it and then his front not wearing it before they all walk towards KITT when he takes it off.
KITT destroys the EMP generator on his bonnet and it's visible again 10 seconds later.
In one of the scenes where K.I.T.T. is changing back into his black appearance, one shot in the sequence just shows the side of his white body, with no changes taking place.
Mike was dead and a AED was used to restart his stopped heart. 1) a AED will not discharge on a stopped heart and 2) AEDs stop a heart to let it restart on its own.
During the first chase, when KITT displays the "Knight Industries 3000 Field Tests" screen, The last item shows "High Velocity Breaking Index" where "Braking" is likely meant. Capitalization is also inconsistent throughout the display, i.e. "Nanoskin modification speed test".
When KITT shows Sarah a picture of Mike, he is said to be 6'3" and 185 lbs but his driver's license shows that he is 6'2" and 160 lbs.