You need to take the car to a facility that can properly determine if
the alternator is working.

And find a mechanic that knows what he is doing.

Jeff

Today I went and warranteed the battery for a brand new one and put it in.
The car started right away with no problem.  Idle still fluctuating (1200-
2000) and gradually made its way down to 850 rpms when  it was at operating
temperature. After the initial start I took off the battery terminals and let
the car warm up on just the alternator to check if the alternator was bad.
When the car was warm and at a steady idle I tried turning it off,
reconnecting the battery and starting it again.  Started fine and idled fine,
I disconnected battery again and tried turning on the lights and the car shut
off. Now, I reconnected the battery and started it again, this time when I
took off the terminals the car died instantly and the lights weren't even on.
The alternator is only a year old and I bought it new.  Could the alternator
be shot already? And would the alernator cause the tach to drop to "0" while
the car is  still running?  I also put in the VSS that I had bought a few
weeks ago when the speedo was jumping and tach still dies when I turn the
lights on.  Also, fyi, the check engine light didn't come on.

The thermosensor that controls the cooling fan is faulty. The fan
won't be on at 55 degrees!!
Your battery was wrecked by that stupid fan. And when the battery
can't maintain proper voltage, the ECU is confused.
So reset it (pull a fuse if your car has one, or simply disconnect the
battery) then start the engine and let it idle for 10 minutes. Do not
press the gas pedal during this process.
But fix the sensor and replace the battery as soon as you can.

I have a 1991 Accord with a 5spd F20A SOHC motor that is having problems
today.  I woke up to take kids to school and car was dead.  Car was not
started for 5 days and my wife said that yesterday she heard the cooling fan
running in the garage. Garage is heated to 55 degrees.  So, I jumped the car
and idle was fluctuating and car was running very "choppy".  When I hit the
gas, the engine sputtered and back fired through the throttle body. I left
the car running for the 10-15 minutes that it took me to drop off kids in
truck.  When I came back, car was idling fine(@850rpms) and running smooth.
I thought it was okay now.  I turned it off after another 10 mins and went
back inside.  Now, I started it and went to work and everything seemed okay.
When I went to go to lunch, battery was almost dead (laboring to turn over)
so I let it run for a few minutes, then as I was about to pull off, I turned
on the lights and the tach dropped to "0" like the car stalled but it was
still running.  When I hit the gas it was sputtering and back firing.  I
turned the lights off and the tach went back to normal.  I turned the heat on
and the tach went back to "0".  Hopefully I will be able to limp the car the
6 miles to get home without getting pulled over for no head lights.  

Any input is greatly appreciated.