2006 Mustang GT electrical problem?

[Hammer]

Sounds like another ground problem.

Check all of your battery cable connections, including to the block.

Clean the battery's posts\terminals if needed.

If problems still persist It's time to start looking at other ground locations in your electrical system. Sounds like your radio and the "low fuel" alarm may be on the same circuit.

Since its an '06, I would do the easy\obvious stuff and then take it to the dealership for warranty work.