The "tires screeching on pavement" sound effect is often added while KITT is peeling out on sand or rounding a corner on sand/gravel/grass. Screeching sounds would certainly not be heard while driving on such surfaces.
Every time KITT drives into the mobile headquarters we can clearly see that the car just barely fits, with only a few inches clearance from each side, yet Michael is able to swing the door open and get out.
In 'Soul Survivor' Michael is driving along the road talking with k.i.t.t on the opposite seat.
When he stops the car after running out of petrol, he opens the door briefly and you see k.i.t.t isn't there. He is there again when he offers the car to the guy he flagged down on the road.
The copyright date at the end of the credits on the first (pilot) episode shows the roman numerals MCMLXXVII (1977) instead of MCMLXXXII (1982). Some people have suggested that this may have been when the idea was conceived rather than produced.
In "Knight of the Phoenix", a stunt driver wearing a hood is visible in KITT when the car inches for ward behind the guard as Michael is trying to escape Comtron.
In the episode "Big Iron", when Michael and KITT are about to be buried under tons of gravel, some shots show that the tractor tumbles a Pontiac Trans Am, rather than the concept car used in the series.