I was leaving work today and my car was still cold and i hit the throttle in first gear not hard but enough to make it hestitate then come on for about a 1-2 second burst, no high rpm. Imediately I had a new noise that sounds...no kidding like a heat shield on a catelytic (sp?) converter came loose...except I have none. The noise is not all the time but does come up in each gear with a little rpm. No change in oil pressure or how it runs (no miss)....just a disturbing noise. How could I have hurt it? what my be wrong?