Amp Readings

Had to put a new battery in my newly purchaced 89 GT. I am noticing the gauge is reading a bit low at idle and then when I accelerate and start shifting the gauge bumps up slightly. This car is pretty much stock except for exhaust and cold air intake. Just wondering if this is a normal reading.
 
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this is normal to a degree, due to a lower engine rpm, however you'll need to verify the voltage with a voltmeter, or have a load test performed on the alternator. this would be a great opportunity/excuse to change over to the 3G alternator, it a much better alternator and puts out 130 amps, versus the stock 65 amps. I did mine years ago using an alternator off of a 97 mustang V-6. Don't forget to get the wiring and fusible links from the donor car. there is a little grinding to be done, but you will be well-pleased.
 
Do you have under drive pulleys?

The stock voltmeter isn't all the accurate. I recommend putting a volt meter on the battery at idle. You should 12v or more. Of you give it a little gas you should have 14v. Under drove pulleys can lower idle rpm speed that the alt spins and cause undercharging issues
 
No aftermarket pulleys, but after taking the alarm out of the car and putting back the same battery I noticed the amp reading went up about an amp and a half. Now I'm trying to figure out what I removed that is causing the fog lights to not come on. Prior to this they came on independently with or without the headlights. Now nothing at all just headlights. Thought the trunk release was messed up, but realized the ignition has to be engaged for that to work. Noticed that the fog light problem is common. Just strange that they are on there own fuse and cause problems with headlights. Just something else to try to overcome. Everything that I removed was somehow connected to that alarm mod. Didn't have anything left but a small ga. Brown wire that is still not attached. That brown wire was the same wire that caused the hatch to open when I flipped on the headlights. Thought I was in a 3 stooges moment. That brown wire must somehow be attached to the trunk button maybe for some keyless entry option.
 
Feel like a dumba--. Lets just say I got my problem solved I now I'm a rookie and pulled a rookie move. All is correctly working , I have some relief in my car mechanic abilities, and now i can get some sleep. I guess since I am a plumber I'm only suppose to know 3 things, shi- runs downhill, don't bite your fingernails, and payday is on Friday.
 
Feel like a dumba--. Lets just say I got my problem solved I now I'm a rookie and pulled a rookie move. All is correctly working , I have some relief in my car mechanic abilities, and now i can get some sleep. I guess since I am a plumber I'm only suppose to know 3 things, shi- runs downhill, don't bite your fingernails, and payday is on Friday.
You missed one -
Don't pick your nose...

Actually water and electricity are similar it the way that act in a closed circuit environment.
Electricity flows like water:
Voltage is like pressure,
Current in amps is like volume,
Resistance is like the kink you put in a garden hose to decrease the pressure or volume.
Power is pressure multiplied by volume or voltage multiplied by current (amps)