Random Q's: Battery voltage, vibration
 

I think my batter may be getting weak, it looks pretty old (I've only had the car about 6 months or so). When I turn on my turn signal, press the brakes, or roll down the window the voltage meter in the car takes a dive..Is this just the electrical system in the car or is the battery weak?

At idle my car (idling around 600-800 rpm) has a little vibration in it. Enough to wiggle the shifter when it's in neutral and wiggle my rear view mirror a bit (in it's defense the rear view mirror is out of it's grove and wiggles very very easily).
It doesn't get worse at higher RPMs (in fact it seems to disappear when I'm accelerating)..is that anything to worry about (bad apex seals or a engine mount?) or is that just the rotarys vibration?
Also at idle the car has a different sound every now and then....
BrppbrppbrpppBBBBbrppbrppbrppBBBB It isn't loud, and there isn't any missing or anything under acceleration.

Add more grounds. The negative battery cable on a 1st gen goes to the long starter bolt. What you should do is add another ground from the battery to the chassis, and reground the engine to the chassis (as I'm sure the old stocker is pretty thin and probably covered in oil/crud, if I remember the engine bay of a 1st gen correctly)). The more grounds, the better. Add as many as you think is necessary, then add some more. Seriously. Now think of the thickest wire/cable you'd like to use, then add a little more girth and it'll probably be adequate.

You should have seen the grounds on Dan Atkins' 13B in his B2200. They were pretty healthy.

As for the vibration, your motormounts might be sagging. The one on the intake/exhaust side of the engine gets torqued down when the engine is producing power, so it tends to wear out. I had a funny vibration that went away with a motor mount swap.

The occasional funny sound could be a number of things. I don't know much about the Nikki or the Rat's nest, so I'll let somebody else handle that question. Then again, it could be a slight misfire. What type of spark plugs are in your engine, and how old are they?

Crap, I should have mentioned it's a GSL-SE.
1984 GSL-SE with close to 73k miles.

Well with my 83 GS, I noticed that the voltage read 15 after I took it out and put it back in. I also noticed that when i pressed the brakes, the voltage would drop down suddenly. Come to find out, it was a dirty battery post. I cleaned the battery post and the connector and problem fixed. Could very well be something easy as that. May be bad wire also. I would change the ground wire and if anything if it doesnt fix it you at least know its new lol.