when i first start the car its fine the pump primes and everthing. But i noticed today after i turned it off i heard a hummming sound. its sounds like the fuel pump but the sound isn't constant. it'll humm and then stop for a few seconds and then start agian. And then after an hour it stops all together. IDK 93' H23

 

all fuel pumps make humming/whirring sounds

esp if you've gutted the rear seats. it makes it louder.