The car has always been good with volts but recently they have seemed to drop. the battery tested out ok so i figured since the alternator is 10 years old i might as well replace that with a new ACDelco. Even after the new alternator the volts are still lower than what they should be. it seems to hang out at right about the top of the dotted red on the gauge. i dont know what else to check?

 

have you checked the cables?....all the connections?....checked out the grounds?

 

The guages in the f-body are not the most accurate. May be worth a charging system check at one of the local chain stores. You may have hit the nail on the head. Alt is 10 years old so is guage!
just my 2 pennies

 

most likely it's your guage mines 10 years old and reads around 10-12 v, best way is to go with a voltage tester since the guage might be off.

 

check your grounds....might be worth a shot

 

I agree with a few of the guys above. Don't trust the gauges they're prolly off. Just get a DMM and go test it out for real.

 

Yep check the voltage at the alternator with the vehicle running, voltage at the battery, and other places to see how much of a drop there is. Should be easy to tell if it's the gauge or if there's actually a problem.

If there is a problem, it's one of these:

alternator (which you already replaced)
battery
wiring- battery cables and charging system wiring are most important, then ignition wiring, then everything else. A bad connection somewhere can significantly reduce the voltage.

 

thanks for the helpguys where are the grounds?

 

I believe the grounds are on the driver side at the engine and the frame if I remember correctly. Be sure they are clean shiney and not cracked. You should however check the voltage across the battery when the engine is running like these other guys told you.

 

well after the car had sat for two days i tried starting it up and it took a while, felt like the alternator had to spin a little bit to give enough juice to start the car. Would this mean its the battery? seems to be losing juice even when the car is off.

 

Cranking slow is one issue, not starting right away if it is cranking fast enough is another problem entirely. At no time during cranking does the alternator produce enough current. So we have to determine if your talking about slow cranking, or just delayed firing.

First go back and check everything these guys told you to. Pull the battery cables and check the pads for corrosion. Check the positive cluster on the passenger inner fender near the battery. Check and clean the grounds at the frame and the engine.

2nd, now check the voltage across the battery before, during cranking and after the engine starts up. The voltage across the battery should not drop below 11 volts when you are cranking the engine. After the engine fires up, the alternator should have the voltage across the battery close to 14 volts. A bad battery could cause both those readings to be off. Before you go replacing anything, have the item tested. NOT at autozone or advanced.

One other issue to contend with. There may be something draining the battery down when all is shut off. The most notorious is those big thumping amps. They always drain the battery down when the car is off for some reason.

Do the checks I listed above.