Weird noise coming from rear of jeep after short trips. When I drive just around town, everything sounds fine. But after say a hour drive,at idle there will be a distinct buzzing noise which sounds to be near the gas tank. Noise fades away while accelerating. Help please! Could it be my fuel pump going bad? 91 Cherokee sport. 4.0 high output

I think you are correct about the pump since that would be the only thing that would make a buzzing sound back there.

Yes. It definitely could be your fuel pump going bad.