Alright, so I had a very noizy */C and it wouldn't make boost unless it was really cold outside. The minute it started warming up, it felt like the belt was slipping and the car would buck like a horse as soon as I went above 0 boost.
I replaced the coupler yesterday, the play is gone and so is the noise...but I still don't have any boost under load. The belt is recent (less than a year old) and it'* properly tensioned. I don't know what to do to troubleshoot this problem.