A number of embodiments of engine induction system and fuel injection systems for increasing the engines combustion efficiency by maintaining a desired ratio between the intake system volume between the throttle valve and the intake port and the exhaust gas volume. This requires a close positioning of the throttle valve to the combustion chamber, and thus results in quick throttle response. A fuel injection system injects fuel into the intake passage, and a number of embodiments of buffer valves are employed so as to maintain stability in combustion when blipping the throttle under no-load conditions. In addition, arrangements are disclosed wherein separate throttle bodies are employed but that utilize the fuel rail as a means for connecting all of these throttle bodies together to provide a unitary sub-assembly. In addition, an improved throttle position sensor and associated controls are mounted in close proximity to each other on the throttle bodies in many of the embodiments in order to reduce external wiring and improve signal transmission. In addition, the control system employs an arrangement for compensating for a non-linearity in the output of the throttle position sensor.