At the end, Devon rides off on his motorcycle and even pops a wheelie as he goes. A minute later, while Michael and April are chasing him down in KITT, the closeups of Devon on the motorcycle show the black throttle cable hanging off of the handlebars and not connected to anything.
When KITT is tumbling down the embankment the undercarriage gives away the fact it is a plastic model car being used.
The Honda XR motorcycles used have 4 stroke engines, but the sounds heard are that of 2 stroke engines.
There is a clear dent in KITT's left fender in one shot during the climax. In the very next scene the dent is not there.
When KITT goes through the hay bales, it's clearly not David Hasselhoff driving. The driver is wearing a different colored shirt and jacket and the drivers hair is different.
Hand of crew member is seen to close Kitt's door as Michael gets out to investigate the warehouse.
At the end when Kelly gives Michael the motorcycle helmet, the studio lights illuminating the scene are reflected in it. This happens again a moment later when Devon rides up on his motorcycle and the same lights can be seen off of his helmet as well.