A tubing injector for pushing or pulling a tubular string axially into or out of a well, the tubular string comprising a plurality of oil field tubulars connected together with tubular connecting elements, the tubular connecting elements having a larger diameter than the tubulars, the tubing injector having: a) a housing structure; b) a plurality of gripper block assemblies attached to at least two drive chains, the at least two drive chains substantially parallel to each other and rotatably disposed in the housing structure, the plurality of gripper block assemblies configured to make contact with and apply force to the tubular string, wherein each of the plurality of gripper block assemblies comprises: i) a pair of gripper blocks rotatably disposed in a housing further comprised of two housing halves, ii) a pair of eccentric shafts rotatably disposed in the housing wherein each of the pair of gripper blocks is rotatably disposed on an eccentric shaft, and iii) a spring disposed on each of the pair of eccentric shafts configured to bias each of the eccentric shafts to a starting position; c) at least one motor operatively connected to the at least two drive chains, the at least two drive chains positioned in a spaced-apart configuration to create a passageway for the tubular string to pass therethrough; d) at least two pressure plates or beams each operatively connected to at least two hydraulic cylinders, the at least two pressure plates or beams configured to impart a transverse force on the at least two drive chains when the at least two hydraulic cylinders are engaged thereby causing the plurality of gripper block assemblies to grip the tubular string; and e) a plurality of rolling elements disposed between the at least two drive chains and the at least two pressure plates, whereupon operation of the at least one motor urges the at least two drive chains to move, thereby causing the tubular string to move axially into or out of the well when the plurality of gripper block assemblies are applying force to the tubular string. a) a housing structure; b) a plurality of gripper block assemblies attached to at least two drive chains, the at least two drive chains substantially parallel to each other and rotatably disposed in the housing structure, the plurality of gripper block assemblies configured to make contact with and apply force to the tubular string, wherein each of the plurality of gripper block assemblies comprises: i) a pair of gripper blocks rotatably disposed in a housing further comprised of two housing halves, ii) a pair of eccentric shafts rotatably disposed in the housing wherein each of the pair of gripper blocks is rotatably disposed on an eccentric shaft, and iii) a spring disposed on each of the pair of eccentric shafts configured to bias each of the eccentric shafts to a starting position; i) a pair of gripper blocks rotatably disposed in a housing further comprised of two housing halves, ii) a pair of eccentric shafts rotatably disposed in the housing wherein each of the pair of gripper blocks is rotatably disposed on an eccentric shaft, and iii) a spring disposed on each of the pair of eccentric shafts configured to bias each of the eccentric shafts to a starting position; c) at least one motor operatively connected to the at least two drive chains, the at least two drive chains positioned in a spaced-apart configuration to create a passageway for the tubular string to pass therethrough; d) at least two pressure plates or beams each operatively connected to at least two hydraulic cylinders, the at least two pressure plates or beams configured to impart a transverse force on the at least two drive chains when the at least two hydraulic cylinders are engaged thereby causing the plurality of gripper block assemblies to grip the tubular string; and e) a plurality of rolling elements disposed between the at least two drive chains and the at least two pressure plates, whereupon operation of the at least one motor urges the at least two drive chains to move, thereby causing the tubular string to move axially into or out of the well when the plurality of gripper block assemblies are applying force to the tubular string.