Help it sounds wrong...


Help please,
I've got a Cuore (1998, automatic) and 2 days ago I noticed the enginee seems to sound louder and lower as soon as I put the foot on the accelerator - doesn't sound healthy at all but seems to be perfectly okay otherwise. I travel a fair bit and couldn't get to a garage, no obvious problems (no accidents, major bumps, hanging/damaged exhaust or other) and when it get's to 50 mph and over it sounds almost normal again, the minute I slow dows it comes back - more a roar then a quiet humming... If anyone has any thougths at all I'd really appreciate it because I'm stuck at work, not sure when I'll be able to get to my garage and I'll need it a lot this week as luck would have it Sad