Once again Paul Danner simplifies even the most basic diagnosis.
If your vehicle is experiencing charging problems, it is likely the alternator, but first eliminate other possibilities such as a loose or broken alternator belt or a blown fuse. Alternators, just like any other mechanical component on your vehicle, can fail due to use and age.
Peter shows a sometimes forgotten way to check for low voltage issues. By checking the ground side for voltage drop Peter speeds up the process and shortens the diagnostic time.
The most common causes of fuel injector failure are blockages of the pintle due to heat soak, internal shorts, and water from fuel contamination. The largest contributor to fouling of the injectors is heat soak. This is an uncontrollable occurrence on all vehicles. Heat soak occurs every time the engine shuts down. The remaining fuel on the nozzle evaporates due to the increase in temperature and lack of airflow.