Ok. Well, i'm not a lawyer or anything, but i think a judge would agree with you, that you paid for something to be done, and he did not do his job correctly, and the car doesn't run properly. So imo, you dont owe him jack, until he does his job, and fixes it. I cant see someone honestly being like, "You owe me money on the car i have yet to fix for you." you know? This is all a matter of opinion, and in no way a court of law. BUT i think that this is america, and if you get paid to do something, do it right or dont expect to get paid. If A landscaper comes to your house, and mows half the lawn and expects to get paid, he's got another thing coming. I honestly would not pay that guy a dime of what you owe, before he gets it running properly. I wish you the best of luck, and hope everything turns out well on this.