i dont have another stereo with line level outputs.

but i just got in my car and put all the eq settings to 0db and loudness off, everything to what you said. and turned a song up that i had previously heard distortion on and it was perfect and really loud. then i put back my eq settings which is all lower than 0db. and still perfect sound. so i started driving and it sounded great i thought it was fixed. then i started getting some distortion and it seemed like the longer i drove the worse it got. the same song that was perfect before now has a fuzzy cracking sound. it wasnt loud but it was definitely noticable.

and i thank you for all the help that i have recieved so far.