I just purchased a used 2007 G6 GT Convertible almost 3 weeks ago and I've encountered 2 problems already. I just had the resonator replaced because of a whistling noise on acceleration. Now, when I'm driving & I turn, the car makes almost a grinding noise & then when I completely stop but remain in drive, the grinding/vibrating noise still remains unless I put the car in park, reverse, or even neutral. Any idea what this could be??