Pontiac Repair: 1994 Grand Am 3.1 Running Rough Low Voltage, hash mark, exhaust noise

Question
Hi, I have a 1994 grand am GT with a 3.1 and 217,000 miles. It has always ran great and just recently it started running really rough. It shakes bad when in park or stopped at a light. It seems to run just a little better as it warms up, but it still is rough. Also, it is louder than it used to be. It really doesn't seem to be exhaust noise either, and the exhaust is only a year or two old. The voltage meter is a little low too. Sometimes it will come up to normal, but most of the time it sits above the first hash mark. I had the alternator and battery tested at Auto Zone and they said they appeared to be fine. Any help would be greatly appreciated.  

Answer
Hey Kyle:

This could be a whole bunch of things and with over 200K it adds in a whole lot more. Start with the basic things like tune up parts plugs,wires,fuel filter etc.. for the running rough. Maybe dirty injectors. With that many miles on it it's not going to run like a new car by any means. The throttle body is more than likely all choked up from carbon clean that out it will help with the idle. As for the volt meter being low it could just be the gauge is bad but if it indeed is low it will make the car run weird as well The ignition system needs full battery voltage to run correctly as does the fuel pump. What could be wrong there? Maybe a bad ground on the body and engine corroded or loose. How about the connections at the battery it's self? the noise you are hearing may not be engine related it could be coming from the alternator I have seen them start to make noise before they completely stop working try to isolate the source of the noise. My guess it you have multiple things here all contributing to the way it's running. Good luck :)