Hello, new to forum. I have a 2005 base 997.1 and recently when I turn the ignition on I periodically get a loud static or hissing sound in the speakers. This happens whether the audio system is on or not. All of the display functions work except audio. It is unaffected by engine speed and occasionally persists for about 30 seconds after the ignition is off. I can start the car in a few minutes and everything works normally, usually for several weeks. Has anyone experienced this of have a cure?

Thanks

 

That symptom is usually an amplifier grounding issue or the amp is starting to go bad.