My car runs well, but it makes a loud knocking noise.
First the location of the knocking must be determined. The fix will vary greatly depending on the cause of the noise. Suspension components may have become worn or broken. Brake pads with worn hardware can also make some noise as they move around. Engine noises can be caused by many things. I recommend having an experienced technician inspect the vehicle to pinpoint the cause of the noise and perform the necessary repairs.