I have a 2005 Cadillac CTS 3.6L and I am getting a hollow rattling noise when I accelerate to 1k RPM and then to 2k RPM, but it subsides after that, while steadily driving. Possibly the AC Compressor is going? Would it be something else? If i were to replace the AC Compressor Relay, would that solve the noise problem without having to replace the compressor?