Bought a new battery and alternator this winter for my 93 fox body because last fall before the car got put in the garage the alternator and battery were bad. The car started and ran fine all winter. I happend to loose my only key a few weeks ago so i had to get a whole new steering column because i did some damage to the lock cylinder housing trying to get out the old one.took it out finally for the first time this spring and it drove good up until i hit a few bumps and would almost stall. Then eventually just died on me. It will want to turn over but won't. Now I've tested the battery and the alternator car running and car off. While its running it runs a little below 12 volts when it should run between 12 an 14 volts. When I turn the lights and stereo/subwoofers the car will die. just looking for help on what to do next.