Continuity: The old pickup truck that leaves the Joseph house on the reservation has 10-lug rims, and when it is returned by Victor and Thomas, it has 5-lug rims on all 4 wheels. Obviously it's a different truck.
Factual errors: There is no way that one bus driver could have driven the same bus continuously from Idaho to Arizona. Federal law would prohibit it.
Errors made by characters (possibly deliberate errors by the filmmakers): Thomas says that Victor's dad looks like Charles Bronson in Death Wish V, the one where he fights the Asian gang. It is actually an Irish gang in Death Wish V.
Continuity: When Thomas offers Victor money to help get him to Phoenix, his braids change position. In one shot, they are both in front. In the next shot, his right braid is over his shoulder. This repeats several times.
Continuity: When 12-year-old Victor beats Thomas up right after his dad leaves, he is wearing a white and red shirt under his button-up shirt. After he begins running, the undershirt changes to a completely red muscle-tee.
Continuity: When Victor drops Thomas off at his home, you can see the shadow of the rear-view mirror, cast on the truck seat. In the next scene, when Victor stops at his home, the mirror is gone but the bracket is there.