Bang, right before inducer draft motor starts
 

I just got a new Goodman high efficiency 95% furnace installed 2 days ago. It worked nicely from the start, but now two things are starting to worry me.
#1. It seems the inducer draft motor/fan is running louder. - is that normal?
#2. (This just started about 3 hours ago) There is a noticable "bang" in the furnace right before the inducer draft motor starts. Is that normal? It wasn't there before.

Could be something fell into the inducer. Call the guys back who installed it.