Engine Noise - '06 Cobalt LT - Help appreciated.

[bowtiesdime]

Hi guys, first time on the site. Looks like a pretty good resource. I'm dealing with some engine noise in my '06 Cobalt LT 2.2 auto sedan. I'm no mechanic by any means, so I'll describe the problem the best that I can. Hope you can help. When accelerating, this "rev" noise from the motor gets louder and louder. But I can feel the gears shifting and can see it happening on the tach, but it's just a constant, building, increasing "rev" or loud engine hum and it gets really loud by the time I hit 55 and above. Kind of like a "waaaaaaaaAAAAAAAAAAAAAAA." Then when I back off the gas, the "rev" noise slowly decreases. It's really getting annoying and my wife has to practically blare the radio to try to cover up the sound on the road. It's like a jet engine or something.

I keep trying to describe the problem to my mechanic, but I don't think he's taken it out on the road to replicate the issue. Just starts it up in the lot. He just cleans out the throttle body, thinking that the butterfly is sticking/not completely closing because of carbon buildup or something. But it's since been cleaned out and the noise continues. I just need this issue solved, because I've noticed that my gas mileage has really taken a serious hit. It's ridiculous. My full size chevy truck is better on gas right now! Hope someone can offer a helping hand, as I'm really losing my patience with this car. Please let me know if I can in any way be more specific.

Regards,

Brian

[PoweredByLE5]

Can you maybe get a video? I can't really tell you without hearing it.