Less than a hundred years ago, driving a car was as much a novelty as shopping for one. In fact, you didn't even need a driver's license to purchase a car. So, it's not surprising consumer protection was as shaky as a new driver. "Buyers beware" was the phrase of the day.
Today, sellers have to abide by laws that protect those consumers purchasing vehicles. For example, all product warranties must be disclosed before consumer purchase. Buyers who feel misled can sue the seller, and buyers who win have the right to recover attorney fees.
Since discovering your car is a "lemon" can take time, each state has its own set of "lemon laws." These laws differ from state to state, but the following general principles typically apply in some version. For example, in California, lemon laws cover the first 18 months or the first 18,000 miles. In Massachusetts, you have one year or the first 15,000 miles. While both states define a finite amount of time, they just permit varying degrees. If the problem on your car has been repaired four or more times, you've lost 15 or more days of vehicle use due to repairs, and your car's condition can cause death or injury, you should check into your state's lemon law regulations.
If your newly-purchased car turns out to be a "lemon," it will be legally labeled a "lemon." The good news is no one else will be blind-sided. Adherence to the "lemon law" is insured since "lemon" is stamped on the official documents needed to transfer the vehicle.
The "lemon law" is much like laws governing the sale of salvaged vehicles that have undergone significant repairs following an auto accident. The car can be sold, but the car's history must be disclosed to the buyer. Like any relationship, you want to know the history of pitfalls before you decide to commit.