Gmc Envoy engine sound.?

[cartierstunter]

I drive a 2005 gmc envoy. When I start my car up and pull out the driveway, I begin to step on the gas and I hear this loud humming sound that last for about 20 seconds. Is this normal or do I need something flushed? Someone please let me know.

 

[handyclown]

go to shop have it looked at