I'm not an expert in textual criticism, but if I am not mistaken the King James Version has had several updates from the original, and that at least 90% of it was taken word for word from an earlier translation known as the Geneva Bible (which was also the first bible translation with annotations and study notes).
Plus, isn't the text taken from the Texus Receptus, which takes the majority readings over all others? That's a problem for a defensive argument, because we don't know whether someone mass produced an alternative rendering and left the others less copied. If I'm mistaken, we may have mass copies of some odd renderings that don't make sense in the flow of the Greek. You will find passages, even one whole chapter, found in different places within books of the the manuscripts, or scribal notes that made its way into the translation. Erasmus admitted in his early editions of the Greek New Testament that 1 John 5:7 isn't found in the original. It makes sense, since not even the Nicene fathers who defended the Trinity, or even Augustine in the West, has been found to quote this passage at all in their works. You would imagine that this would somehow be briefly mentioned for being so clear.
The last thing to consider is that some renderings don't make sense in context. One of those I've stumbled upon was Revelation 5:8-10 where the four living creatures are singing that they were taken from every tribe and tongue and nation, whereas the base text of other translations exclude themselves from the song. Was that a careless pick?
The King James is a good translation overall, it had played also an influential role among the Puritans and other great men's lives, as well as retain and encourage very high level English literacy in the English world for centuries. But let us not get caught up with the whole inerrant translation argument. God inspires his word to be true in all that he says and teaches, inerrant in doctrine. Inerrancy doesn't have to mean perfect manuscripts, they all are 99% the same, and the 1% difference is mainly punctuation or alternate readings that do not change the inerrant truths (like in Jude one says the Lord led the people out of Egypt and another says Jesus).