On my 93 yj, 4cyl, 5 speed my voltage gauge is always showing a different reading. I know it should be around 14.5v, but sometimes when i drive it, it is showing 12 and i can turn it off and on and it will be up to like 13 volts or 14volts. I put a new belt on, and the alternator looks new, just wondering if anyone has any ideas?  

Ya might have some bad connections. Check the battery cables and connections for corrosion. Also, as long as it's above say 12.7 volts and under 14 you should be good to go.