Audi=No fault code, no idea
Interesting stuff Cheese.
I traced my problem to plugs. I took the std plugs out at 4k miles and put a mega tester on them. Checking for a leak to earth at 500v two were fine and came up as infinity and to had a leak of 400m ohms. Basically a leak to earth that would have got worse under load and compression. One plug failure at 4k is bad luck, two is a pointer to a fault in the plugs or their unsuitability for the engine.
I note the Yanks in the link above are having problems across the range from 2.0T to 3.2 and so its going to be something common across engines.
My thinking is we are mislead a lot of the time because a minor fault can shut down the system momentarily. I know for a fact that one injector failure can cut power to the other 3 to save engine damage or a pollution disaster :-) . so it seems possible that a bad plug could cause the system to momentarily shut down causing a small misfire to become a ignition cut/jerk on the road.
I can only guess but i think the problems are very small but amplified by the Canbus system under stupid rules that might, god forbid, allow a hydro carbon to escape !!!!
Ibis white Revo S3 and now matching Vivaro LWB HR 2900 :-)
Many people are alive because its illegal to shoot them.