Audi 2.4 V6 issues
 

My sisters partner has an A6 with the 2.4 V6 petrol lump.

Engine idle is all over the place, and the idle speed hunts up/down all time. The issue is more pronounced when cold, but is still there even when warmed up.

Now I've hooked up VCDS and a scan shows a camshaft position sensor fault, which I hope is the cause of the idle speed surging.

I also looked at the engine measuring blocks, and regular misfires are being reported against bank 1, but bank 2 is completely fine. You can sit with VCDS monitoring bank 1 and watch as the misfire count increases in line with the RPM changes. I can only hope that replacing the cam sensor will fix this, seems feasible if the sensor is giving the ECU rubbish info. No misfire fault codes are logged, but its difficult to diagnose because the engine light is always on as both Bank1 and Bank2 cats report below efficiency.

Update to this, I spoke to my sister earlier today and the idle problem has got a whole lot worse with the added complication it now lacks power. I can only guess the cam sensor has failed even more and the car is running possibly on 3 cylinders.

The cam sensor has not yet been replaced, but she does have the part that I am meant to be fitting next weekend. However the car is in Lincolnshire and I am in Dorset, they may attempt to drive the car to me next weekend depending on what happens during the week.