when i bought my mustang, it has a pos stereo in it, worked just fine, but it was poor quality, so i bought a decent one from a pawn shop, took it home, tried to install it myself, not sure what happened, but i couldn't get it in, so i took it, half installed, to a electronics store, asked the guy to do it for me... the wires that went to all the speakers, had electrical tape splices between the door and the body, so when he was installing the deck, he would try it, the stereo would turn on and "one of the speakers would short out" and the deck would turn back off...
so after replacing 5 fuses that were apparently blown in the car (did not know this before hand) and re-running the wire to 3 of the 6 speakers, he gives up, says he can't get it to stay on for more than 1 second... but because it's not working, he won't charge me anything... i think him, hop in and drive away, listening to music... what i later figured out, who ever had installed the previous deck had changed the accessory power wire to key on power... the installer from the electronics store had been trying it in the acc position, and getting a flicker of power, turns on for 1 second and back off...
same car, when coming back from the test drive (private sale) i heard a crunch in the suspension, when going over a small bump/hill asked what it was, i was told a bushing was worn out on the top of the strut... after buying it, found out it was a broken swaybar end link, the two halfs had hit eachother and made the noise... $20 in parts and it was fixed...