Abstract: A downhole pressure pulsing apparatus comprising: an upper sub that comprises a tube having a hollow interior through which fluid can flow; a middle sub that comprises a tube having a hollow interior through which fluid can flow; a lower sub that comprises a tube having a hollow interior through which fluid can flow; wherein said upper sub is connected to said middle sub by a connection such that the hollow interior of said upper sub 1 is in fluid communication with said middle sub's hollow interior; wherein said middle sub is connected to said lower sub by a connection such that the hollow interior of said middle sub is in fluid communication with said lower sub's hollow interior; an impeller assembly, wherein said impeller assembly comprises an impeller that is rotatably mounted inside said middle sub's hollow interior; a stator, wherein said stator is housed inside said upper sub's hollow interior and wherein said stator directs fluid flow into said impeller; a cam assembly mounted within said lower sub's