I have a 96 Bonneville SSei supercharged with 136K. When I start up, there is a noise coming from the right rear area which sounds like growling. the noise is independent of engine speed, vehicle speed, and braking so I'm fairly convinced it'* not a critical mechanical component that is being destroyed by my continuing to drive it. the noise eventually goes away after 5-10 minutes.
Is there anything I should look for when I'm under there this weekend?
what components are in that area?
fuel pump?
exhaust pipe mounting?
muffler?
else?

what else should I look for or test to get to the source?

thanks

Look around at any shields that are in the area. Could be one rusted loose.

That is your fuel pump. Could also be your rear suspension pump.

Does the 96 still have load leveling? If so it could be the pump running to level the car out.