I have a Carrier Performance 96 furnace (58UVB) which is about 1.5 years old, has worked perfectly since install.
I've noticed lately a noise i've never heard from it before, sounds almost like a buzzing noise... i listened closely and it appears to come from the gas valve. I believe this to be the case since the noise stops immediately after the thermostat stops calling for heat and the burners shut off.
When the furnace first starts up, it runs exactly the way it should up until about 7-10 mins of run time...and then intermittently it will start making the sound in the video below. Initially just on/off for a second or 2 at a time until after a couple mins it's just constantly doing it til the cycle ends.
Here's a quick video I made, it's dark..but you really just need the sound anyway:
Anything to be concerned about?