For some reason, when I am backing up, if I go anything but a very slow speed I hear what sounds like (not saying it is) rubbing noise like a tire rubbing somewhere. I don't know what is causing it, and can't seem to track it down. It doesn't seem to matter if I am backing up straight, or if the wheel is turned, but if I back up my 2000 GTP and press the accelerator pretty much at all, it will make the noise. If I just let it back up without pressing the accelerator, it doesn't make the noise because it is a slower speed.
What could I check?