alternator may be bad but somethings fishy

[captainclutchkick]

ok heres what is going on, my battery went dead from sitting so icharged it up to 12.5 volts and it still wouldnt start my car so im jumped it and it astarted fine and my rev speed meter was showing 14.4 volts so i figured my alternator was working ok becuase it took the battery from 12.5 to 14.4. i drove the car around the block and the rsm showed a consitent 14.4 volts, but when i would rev the car hard it would drop doewn to unter 10 volts and almost die. i drove it easy back home and pulling into my driveway i reved it up a little and it died. when i turned the key to the off position it registered 12.5 again so i took the battery out and tiook it to autozone and they said it was still good but need to be charged. so is my alternator bad? i just dont see how it could be bad it took the battery from 12.5 to 14.4 at while the car is running. but why does the car almost die whren i rev it is my alternator bad??

[positron1]

Could it be a grounding issue? Check the grounds.

[captainclutchkick]

shure where are they?

[krayton]

try just cleaning or changing your battery plugs

when u change the ground, u can check that one too. just follow it down to where it goes to the chasis

[positron1]

There's one grounding cable from your alternator to the shock tower near the battery. I'll have to look up the others.