Purchased a used car in Dec, changed air filters & the check engine light came on, no acceleration. The Knock Senser went out, and when I called the dealership, all they could say was how sorry they were to hear that occurred. Called the dealership and found that there was a recall and that my car is under warranty. But the dealership sent it to the shop for repairs and when I called they said they only unplugged and reconnected the device senor to turn the check engine light off prior to my purchase..