Near the end of the chase with the Branch Brothers through the corn field, they come face to face with Papa in the Combine Harvester on the road. The Trans-Am goes into reverse and the sound of tyres squealing on asphalt is heard. However, they are on a gravel road.
When McQueen stops at a gas station he speaks with Levar Burton through the car window. A piece of trim hangs from the convertible top. McQueen is seen actually fiddling with the trim without repairing it. McQueen gets into the car and the trim is instantly taped up and out of the way.
When Mr. Thorson goes to pick up Bernardo, he fires 9 rounds from a Colt M1911 pistol, a pistol which can hold at most 8 rounds. Since he flipped the slide on the pistol, any round in the chamber would have been ejected, so he should have been able to fire but 7 rounds.
The train chase was filmed using "6000" series CTA train cars (now out of commission). The train is labeled "Ravenswood B" - but Ravenswood trains would NOT have gone into a subway. They run only on ground level or on elevated tracks.
In the Chicago train sequence, when the train they are on leaves the station it has four cars. In the tunnel scene when they get off of the train and the train pulls away, there are more than four cars.
When Papa goes to pick up the Branch Brothers, he gets surprised by a tossed lit bundle of dynamite at his feet. As he runs away in slow motion the dynamite explodes behind him, throwing him into the air and his feet out in front of him as he lands on his back. A second later, grass lands in his face from the explosion behind him, but it comes clearly from the front, thrown by crew.