Recently the music in my car has been going dim, and then returning to normal. I believe that I have a faulty amp. As of now, i'll be driving at some points and the music will be normal, clear sound etc., and then the music will just go dim until i hit a bump in the road when it restores to its normal sound level. Again, this is very frustrating, and i'm looking to replace the amp. How can i test the amp to see if its in proper condition. I dont have any type of special electrical tools etc. Any suggestions would be appreciated. TIA

Agron
1989 300E (107k miles)