Hi, Irratic revs when idle

You need to reset the throttle body. Sometimes you can do this by going out to your car and turning the key to the "on" position. Don't crank the engine - just turn it to on. Let it sit like this for 15 min. Your throttle body shoulld reset. Good luck. Check out audiforums. c o m or audiworld for audi spec issues. Good luck!

If your volt gauge reads low, then the low voltage will send erratic signals to your computer and make it run funny.

Could also be bad gas. Try running premium.

Could also be a mass air flow sensor. But it should throw a check engine light in that case.

Could also be a vacuum leak. Raise hood and listen for suction noises.

My Audi charges at about 14 volts b/c it has heated seats, etc,etc. So start with checking your voltage first.