A few weeks back my mach460 began making a short 2 second unbarable scraching noise when you would turn it on or off. This happened when i had an open exhaust with no cats or mufflers on and i ran it like that for about 100 miles and the whole car would be like a vibrating chair. Ever since, it began doing the noise. I checked the fuse and its still good. Also, when i turn on the radio it takes about 3 seconds until the base begins to work.
I hate the mach 460!! The biggest POS to work on or modify! Anyway, if anyone can help me diagnose or figure out the problem it would be awesome.