Prius Engine Noise When Crusing

Hi Prius Owners,

Searched, but didn't find anything that truly explained my situation. Have the car for about 9 months now, but of recently, when the car is around 45-60mph is makes a clicking sound when I put my foot lightly on the gas on the freeway. So basically, when the car is cruising around that speed, you can hear a slight clicking sound around the firewall area.

Right a little past the middle line while driving, it makes a clicking sound and when I let go of the gas pedal, the sound goes away. Some people have written about a noise issue, but no one has really had it resolved. Any input would be great. Thanks.