1998 A6 Quattro won't idle
 

This has been such a headache! The car won't stay on under 1rpm! You have to keep a steady foot on the gas or it's going to cut off! Even then it rides super jerky and rough! What could be the problem? It was sitting up for about 4 months could that have something to do with it?

I have had this happen if I don't run the car for a while. You could be lucky and just have some bad gas in the car because it has been sitting for awhile. You could try putting some gas in it and see if that helps.