I’m hearing a vibration in the dash on the driver’s side similar to what you hear when the bass is turned really high on the radio. Happens at 60 mph and higher, not all the time. On a 5 hour trip it was pretty constant the whole time one-way, nearly non-existent on the trip back. Suggestions appreciated.
I have an '04 T’bird. Something is loose under the dash and is reasonating when the conditions are correct, certain motor rpm, speed and tire vibration, etc.
Here is a good forum for you to check out. Pose the question there and you are asking primarily owners of '02 to '05 T’birds.
Are you sure that it’s under the dash, and not in front of the firewall? Issues with the gasket to the hood at the base of the windshield can cause odd sounds and vibrations.