Engine Noise - '06 Cobalt LT - Help appreciated!

[bowtiesdime]

Hi guys, 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 of 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" sound 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.

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. 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. 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 soemone 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

 

[DaveBlank]

Sorry, I dont know but others will. Bump

 

[outtamymind]

so you can physically see the rpms increase above what is normal?

 

[ff_drift_lol]

what the hell? did your m,echanic check the front end? rear hubs? sounds like a wheel bearing to me. could be a intermediate shaft bearing as well or an internal tranny problem. most likely wheel bearing or half shaft bearing though.

 

[outtamymind]

thats exactly what i was thinking but wanted to clarify if he was watching the rpms go erratic or not

 

[ff_drift_lol]

yeah but they dont sound like that til they get real bad. if your mechanic doesnt check the front end even for a diagnosis he's not really doing a good job lol.

 

[outtamymind]

nope and they are quite easy to check as well for early diagnosis

 

[ff_drift_lol]

i sometimes find them before they even get noisy. anyway, let's see what the result is and see if i guessed right lol

 

[outtamymind]

i always do the tire wiggle test whenever i'm doing an inspection, especially on my car.