Mitsubishi Repair: 99 eclipse gst alternator belt problems, advance auto parts, eclipse gst

Question
I just bought a 99 eclipse gst and the guy said he changed the timing belt. Well I noticed the alternator belt was squealing. Before I could change the belt it slipped off while I was driving and lost power steering. When I went to drive it to the shop it was spitting and sputtering and I changed the belt. I charged the battery a little and started it up and it still squealed at first. Now it doesn't squeal but it hesitates all the time now and I don't know if I need to change the alternator or what? Please help me out

Answer
Mark,
Your best bet would be to remove the alternator and the battery, and take them both to a shop to be tested.  Stores like AutoZone or Advance Auto Parts can do this for free if you can take off the alternator yourself.  Since the alternator and the battery work very closely together, they greatly effect each other if one has a problem.  That is, if the battery is bad, it will cause your alternator to go bad.  And vise versa.  A quick test you can do if you have a voltmeter is to check the voltage across your battery terminals while your engine is running.  It should be showing a voltage of around 14.5 volts.  If the voltage lingers around 12 volts while the car is running, you definitely have an alternator problem.  It's normally good practice to replace your battery if you have a bad alternator since if may have been a bad battery that caused the alternator to fail as well.
good luck!