I have a 97 accord ex with the f22. The car only has 95xxx miles on it and I change the oil every 3000 miles. I bought the car last march with 89xxx miles on it. I should have looked over it more carefully but I was eager for my first car. There is a fairly loud knock coming from the bottom end of the engine and it is constant. Also when its really cold outside it seems like its worst....what are my options? If i need the motor rebuilt how much would it be?