When the car driven by Harrison Ford is first shown, it has no front license plate. During the trip to the farm, a front license plate suddenly appears.
After Carol drives the Camaro through the wall of the bar, the rear spoiler is almost ripped off and left hanging at an angle. The next scene shows the spoiler intact, and the following scene shows it at an angle again.
When Ken brings out the M16, he tells Jack there is no "clip" in it. No Vietnam War ground combat veteran would say "clip" - an M16 uses a magazine.
Ken says he thinks his father, who is in Detroit, may work on the car line that produced Ken's Camaro. Second Generation Camaros (1970-1/2 through 1981) were only built in Norwood, Ohio, and Van Nuys, California, never in Detroit.