Give us a little more information:
Are you the original owner?
How many miles on the odometer?
Has there been any engine work done?
Who does the oil changes? Dealer? Quick Change?
What oil are you using? Brand and weight?
Did anything proceed this knocking sound? Perhaps an oil change?
How do you drive the car? Easy or road rage?
Any other drivers on this vehicle? Teenager?
With cardboard under the vehicle - any oil drips?
Are you the original owner?
How many miles on the odometer?
Has there been any engine work done?
Who does the oil changes? Dealer? Quick Change?
What oil are you using? Brand and weight?
Did anything proceed this knocking sound? Perhaps an oil change?
How do you drive the car? Easy or road rage?
Any other drivers on this vehicle? Teenager?
With cardboard under the vehicle - any oil drips?