re: Legal question: What are your rights when buying a vehicle from an individual?

Wtodd is on the right track. You may have to prove fraud. Another requirement is that the car had to be defective when exchanged/delivered. I think there may be a presumption of defectiveness if the problem arises in a couple of days, or something like that.

Either way, that’s why you always have a used car checked out by an independent, certified mechanic before buying. I’ve walked away from buying 2 used cars after the mechanic told me there were problems.