In the preferred embodiments an air flow diverting blade is integral to a base that doubles as a collar designed to coaxially attach to the tip end of a typical port fuel injector for internal combustion engines.Upon simple manual manipulation of the set rotational angle of the typically externally exposed portion of the port fuel injector along its longitudinal axis, as typical modern port injection systems allow after installation, the angle of the intra-port flow diverting blade can be selectively varied to either straighten existing swirl and increase top end flow, or, introduce lateral directional swirl to whatever desired angle and intensity in either direction is desired. The functional use of a typical port fuel injector is thereby elevated to a dual function of both tunable fuel and air flow control at the point of induction into a combustion chamber without any modification to existing engine designs or their engine management control systems employed therefore. The flow diverting blade can be configured to divert flow around the intake valve stem, guide and guide boss in such a manner to optimize the overall flow dimension of the induction system of a typical internal combustion engine. The flow diverting blade also provides an effective means by which the proximity and angle of fuel injection, relative to the combustion chamber, can be altered and improved as desired. The flow diverting blade also provides an effective means by which a modest increase in effective fuel injector nozzle pressure and fuel vaporization can be realized during periods of high load.