I am experiencing a high pitch noise from my Trane furnace whenever
the gas flow is open. A repairman said the cause is a high gas
pressure taht the city regulates. This problem only started about a
week ago. The noise would not be much of an issue if the furnace was
not placed in the attic above our master bedroom. Does this diagnosis
sound correct? Is there anything I can do to fix the problem? Should
I get a new furnace (it is only 2.5 years old)?

Thanks.