1985 Celebrity 72,000 miles, V6 2.8 FI

I am having trouble with my celebrity staying started. I went to get and got emissions done on my car and it passed but then it wouldn't start it had no power what so ever. We got a new alternator and still no power at all, then we tightened the positive battery cable and we got power. The next day it drove fine for a couple of hours and then the battery gauge was really low and the car would not stay started. There is power but it will not turn over. It has been spitting and sputtering for a while now. Another thing is the old alternator was a 97 amp and the new one is a 108 amp would that cause a problem with battery power. What can you tell us. Please help I am out of ideas! Thank you for your time.