your shocks or your brake pads are probly loose. You need to check them out. If that's not it then take it to a mechanic.
u joint
I don't know, but I have the same problem with my 2011 Sentra. :(
many many things, Loose lug nuts which lets wheel make knocking noise. Engine will make a knocking noise if it is really low on oil. Some timing belts make a knocking, slapping noise just before they break.These are just a few examples . Have someone ride in car with you as you duplcate the noise and see if they can determine which part of the vehicle it is coming from.
Power Steering?
I experienced a knocking noise in my 03 Xterra and found out is was a bad wheel bearing seal and had to have the Nissan dealership replace it for about $400 (includes labor and parts).
The knocking noise could be one of several things. The wheel bearing, a worn steering or suspension part, or road debris could be causing the noise.
wierd
needs new wheel bearings
a dog
A knocking noise in the front wheels can be a very serious problem. The knocking noise could be caused by bad ball joints. Bad ball joints can slip off the tie rods and cause the wheel assembly to collapse. This problem should be looked at as soon as possible.
if its a knocking noise whilst turning or in really bad cases constant then one of the half shafts constant velocity joints is probably failing due to the rubber gattor
A lower engine knock is usually a bad bearing on the crankshaft. Could be a rod bearing or a main bearing.