I recently changed my fuel filter to attempt to cure a mild stutter during acceleration. The stutter is somewhat better, but there is now a constant electric sort of humming while the car is running, which is not affected by RPM or speed. It is a bit like the noise just after turning the ignition but before the engine turns over, except not as loud. Is this the fuel pump running abnormally? I did not disconnect any part of the fuel pump and used a Volvo fuel filter. Can anyone tell me if this noise is indicating a problem?

By the way, my congrats to whomever wrote the FAQ guidelines for changing a fuel filter.