Maybe you need a whole new crank and bottom bracket. Do the pedals thread in and stay tightened now? Sounds like a lot of play in either your pedals or bottom bracket or both. Bottom brackets are mostly crank-specific, though, so hard to say what you might need to shop for. I tried looking up a Barracuda Oblviion on bikepedia.com but don't see that model. What make and model of cranks are they? You might find info on the backs of the crank arms.