I've had an up-pipe to manifold gasket leaking for a few weeks and just got it fixed. Now that noise is gone i hear a rattling under load that sounds like it's coming from the front passenger side of the engine. I looked under the hood while it was running but wasn't under load so no noise. However, the tensioner pulley beside the alternator was bouncing up and down about 1/4" each way. I'm assuming this isn't normal and is the source of my rattle?