They sent a field engineer out and he couldn't find a fix. That was a month ago - no update since.
At which point they should take the car back (for internal testing/research) and provide a replacement. You need to get Kia corp involved, and if they are already it may be time to lawyer up.
Lemonade law time. Or something like that.
Get copies of your service records trying to get this fixed. This should be an easy case for the lemon law in your state. You can send the dealer a letter with the attempts at fixing attached, with the lemon law quoted (varies by state) and ask them to reply in 10 days as to how they are going to make this right. Address it to the manager and send the letter return receipt certified mail and regular mail. If by some crazy chance they try to refuse signature but take the regular mail one, you can still presume service happened due to not having the regular mail returned. For the certified return receipt, you get a signature back showing that they took it. These types of issues MUST be handled with written correspondence, so they can't possibly try to weasel out of it or claim that you never talked to someone, etc. Plus, by doing this, you do a lot of what a lawyer would do where they would charge you. But you seem to have a solid case. You need to serve them notice.
