Rep Power: 0

My car has been acting up lately. Whenever i sit at a stop light for over 30 seconds my cluster light dims along with the clock and i have a slight misfire. but when i take off everything is fine until the next stop light. my gauges also go crazy when this happens. And when i park my car and try to start it up sometimes its sluggish crankover or doesnt even have enough juice to start up.

so i took a voltmeter and went to town and this is what i got...

with the car OFF put voltimeter on + and - on battery = 10volts
with the car ON put the voltimeter on + and - on battery = 14.3volts

with car ON put the volitmeter on positive on alternator and other on good ground = 14.3 volts

with the car ON and everything i could possibly turn on in the car . put the volitmeter on battery = 9.9 Volts
with the car ON and everything on i put the volitmeter on alternator = 10volts

hope someone can respond to this and help me out

 
Rep Power: 244

Your alternator should detect the load and put out more voltage when there are loads added.

 
Rep Power: 0

so what does that mean exactly?
my whole alternator is bad or could it be the voltage regulator?
could i replace the voltage regulator?

i just got back from being stranded at walmart from having very very dim headlights almost no lights
my battery seems like it no longer holds a charge. but when i jump it with another car an have the jumper cables connected between cars for a few it seems like it holds a little charge but after turning my headlights on for a minute or two all my inside lights and headlights go very dim almost off, then the car stalls.

 
Rep Power: 812

well first off the battery is pretty much dead, even down to 12.0v is pushing it. It should be at least 12.6v under normal conditions. my bet is on an alternator that is putting out some amps, but not as much as it should be. im surprised the charging system light didnt come on. you can grab a battery tender plus and recharge the battery overnight, but more than likely its already ruined to the point of needing replacement after the new alt goes in.