Fuel injectors are controlled by electronic pulses from the vehicle's electronic control module. Injector connectors secure the signal wires to each injector and make the electrical contact. Just like everything else under the hood, they are susceptible to wear and tear. Being very close to the cylinders, injector connectors are subjected to significant vibration, temperature, and chemical exposure. Over time the connection could become corroded or loose, and the fuel signals from the ECM may become weak or might not reliably get through to the injector.