Low revs at tickover

Finally, after changing EGR valve, inlet vaccum sensor and Lambda sensor (before cat) there is no irritating warning lights on the dash for the first time since I bought the car. The diagnose instrument tells me that there is nothing wrong - it starts up fine and pulls away strongly (for a 1.4 petrol) from cold, but after a short while when the engine is up to normal working temperature, the tickover revs drops to 3-400 rpm and becomes sluggish when pulling away. Reversing up a modest slope is a nightmare as the engine stalls if I don't rev like mad - sounds like an old grandma driving a stickshift for the first time in her life :(
Is there anyone out there who has had the same problem? - greatful for for any advice


98 fuel or 95? Try 98. I would also look into the software update, though I'm not sure that's officially offered anywhere any more.
Filled it up with 98 on an almost empty tank a while ago, I even dropped a bottle of injector cleaning liquid in recently and tried some Italian tuning (full revs at low gears for a long time) - no improvement.
Software update? Is that something the Audi main dealer can do?