Just bought a 91 bronco, thing started (repeatedly) fine drove it home stopped for gas and it wouldn't start? New battery new alternator? Radio worked lights worked but wouldn't turn over and the battery kept getting worse. I jumped it and it started out first try. Guy I bought it from says it sat for a long time. I made it home and turned it of and on with no problems. Let it sit for a hour and it started fine? Went to get gas and when I got home I turned it off and turned back on but same thing won't start? I'm confused is it a bad battery or is this common? Not a mechanic and don't no much about cars. Any help will help.