I think I have it fixed now. I changed out the tensioner assembly entirely, I actually used the one out of a 99 Camaro with a 3.8 because it has the option for 2 coolant elbows, not just 1. Anyways, the only difference I saw in the tensioner itself is that it has less play (front-to-back) than the old one. Pretty much the same tension, just less play. I think what was happening was that the belt was moving back and forth just a little bit, causing the belt to be misaligned just a little bit...randomly. Anyways, once it was changed, no more squeak...for now, lol.