I have a 2004 A6 A-Line 2.7T automatic with Quattro and 50k on it. I've noticed that the power the car has is very inconsistent. I'm a commuter so I take the exact same roads with similar driving conditions daily. I've noticed that somedays my car drives like a race car. I have an ear to ear grin everytime I hit the pedal. Other days I find myself really slamming the gas to get it to go anywhere. I have noticed that the sluggishness seems to be more prevalent on colder days. The car continues to drive sluggishly despite whether the engine is warm or not. I'm aware of the typicaly Audi hesitation on rolling stops but this isn't that issue as I've become accustom to that. Just wondering if this is typical or is I should be concerned at all? Could the weather impact this? Seems to be running fine otherwise and no check engines or funny smells at all.

 

My 04 S-Line was sluggish as hell. Problem was bad fuel. A pump gave me regular instead of premium (station has since been closed after investigation). ECU will "de-tune" the turbos to change the air/fuel mixture to compensate. This may be your problem. I noticed that the turbos were less audible when it was eating regular. The minute I got it near empty and filled it with Shell V-Power the change was instantaneous. Performance was back and the turbo woosh was much more noticeable.

 

That's very interesting. I've observed the same thing in regards to the turbos being less audible while the vehicle is sluggish. I'll make a point to fuel at a different gas station to see whether that makes a difference or not.