1999 Toyota Corolla Noise while accelerating

Hi,

I have a Toyota Corollla 1999. Mileage on it is 82000 miles. The car was doing fine. However, It has suddenly started making hoooommmm sound while accelerating. It almost sounds like as if the car has to make more effort while accelerating or its the sound that gives such a feeling. So far I never had to repair anything for my car. Your help in this matter is greatly appreicated.

regards
Shamik