Strange Drivetrain Noise
Car is in sig. Approx 48K miles. Regular oil changes performed at 7500.
This car is used as a grocery getter. We bought it new, so I know it's history. Lately a strange knocking noise has developed when under acceleration. It doesn't seem RPM related, more like speed related. Lift off the throttle and it goes away. I'm not getting any feedback through the steering wheel, so it doesn't seem suspension related. It's hard to tell, but it's almost the same noise the engine air system makes right after the engine is started. I can't remember what that part of the emissions system is called. Are there any common problems which fit this description. Had the power steering recall done and this seemed to surface soon(but not immediately) afterwards.
Thanks for any insight,
2007 Chevy Cobalt 2.2 LT Stock except for custom broken sunroof switch trim