My audi is an a4 avant 1.6 1999. At idle it cuts out at least 2-4 times in an 20 minute journey (depending on lights and junctions!) - does not seem to matter if car is cold or warm, as soon as i hit the clutch the idle speed will either drop to almost zero and kick back in or cut off altogether. Any help really appreciated.

No idea, I'd try the B5 forum or the corresponding engine forum (if AW has one for the 2.6).