Let me know if this is normal. When i'm at a light, my car usuallyidles at about 750 rpm(halfway between the first hash mark and the 1000 mark. Frequently it will drop to about 550-600 and seem like its going to stall out. Can this be fixed or is this normal.
Please advise.

 

its not normal and could be a vacuum leak so check all those pipes, other problem could be a dirty throttle valve

 

Does the car return to the normal idle speed with out you touching the gas?

 

Yeah, it just drops down for a second than kicks back up to normal. It usually does this once at every time i stop.

 

Any other thoughts about this?

 

extra load on the electrical system, car wants to idle normally, starts to lose it, and bumps up the idle to compensate for the load. Like if the AC kicks on, or cooling fans, stuff like that.

-possibility?

 

Possible, but it happens when i'm not even running anything other than my radio. Please dont tell me I have to ride in silent. Although I do love the sound of the turbo and DV.

 

Until you eliminate the vacuum/boost leak or the dirty throttle body as a source, the rest of the realm of possibilities is mute. You need to exclude the most common/obvious first.

 

Occasionally the car (at least everyone I've ever owned) will simply drop or increase a couple of hundred RPM while idling and then return to bt 700-1000rpm. This should not happen everytime you are at a light though. Once in a while is acceptable but an unsteady idle as the norm is not. It still worth you're time though to check it out with a VAG-COM. If you don't have one you'll have to go to a dealer. If no fault codes are read you have nothing to worry about. I'm not sure what sensors Audi uses to control the idle but the VAG-COM will tell if one is wrong.

 

XCLRTT if the throttle body is dirty does that mean he needs a new air filter as well? I just can't think of another reason why it might be dirty.