In the opening narration, John Connor says that he was attacked by the T-1000 when he was 13 years old. This is an inconsistency. In Terminator 2: Judgment Day, John Connor was only 10 years old as shown on the police computer when the T-1000 accesses it.
Sarah Connor's graves states she was born in 1959. In previous movies, her birth year had been given as 1965.
During a conversation between John Connor and Katherine Brewster, John mentions that he and Kate had made out in Mike Kripke's basement the day before he met the T-800. However, this was back in 1995, and John clearly says that it's been 10 years since then, meaning that the year is 2005. This is not true, however, because when the T-850 reset its internal clock, it is possible, if only for a split second, to see that the T-850 stopped on the year 2004. This is an inconsistency because in reality, only nine years had passed, not ten, as opposed to John Connor's claim.