She went in for an oil change, but came out with a brand-new car.

Now a Michigan woman is suing the auto dealer, saying it took advantage of her bipolar disorder to sell her the $32,000 vehicle.

Amy Berner tells the Detroit News she suffers from "impulsivity and difficulty in decision-making," and the dealer used that to get her to sign a $444 per month lease for a Mazda CX-9.

Berner says she had gone to the dealer for an oil change for her car, which she had bought just six months earlier.

Berner's husband says the dealer agreed to take the car back if it got a doctor's letter detailing Berner's condition. He says the letter was sent, but the dealer delivered the CX-9 anyway, and left the keys in the mailbox.

Suburban Imports of Troy says it can't comment on the suit because it hasn't received any legal papers yet.