There are several signs that your fuel pump may be going bad. The most common symptom is the car's engine stalling or misfiring when under load. This is caused by the fuel pump not being able to deliver enough fuel to the engine to maintain proper combustion. Other symptoms include the car's engine hesitating or stuttering when accelerating, loss of power when climbing hills, and decreased fuel economy. If you notice any of these symptoms, it's important to have your car's fuel system checked by a qualified mechanic as fast as possible.