A fuel injector was a part used in certain speeders. Specifically, in the case of Rey's speeder, a fuel injector ring was positioned close to the combustion chamber. Fuel injectors were also components of both Light Infantry Utility Vehicles and V-4X-D ski speeders.
In 3 ABY, following her forced landing on the Outer Rim moon called Toshara, Kay Vess accepted employment with Crimson Dawn. This arrangement provided her with the replacement fuel injectors required to fix her EML-850 light freighter, known as the Trailblazer.