Had the problem with the battery cable being loose on my truck (1992 Chevy 1500K 4.3L v6). What will happen is I'll go to turn it over, and it'll just click like the battery is dead. I have noticed that the ground has a bad connection. I get out, clean the ground terminal and it's fine. So when I get the money I'm going to replace the battery. That sounds sorta like what you're experiencing here. Another problem is that I fried a battery cable a way back (don't ask) and when I bought the new cable it didn't include a new bolt for the side terminal. I had to cut the old one out of the old cable and use that... needless to say you can crank it on there and the cable is still loose.

I'd say check the connections and cables.

 

Not funning you, TOM97, but the right name is alternator, not altrinator.