this is exactly what happened to me last week, i was at the track with my newly broken in RS5, it ran fine for a few tanks but all of sudden it started acting up. I have replaced a few new turbo plugs but no dice. I took the engine apart and it turned out to be the conrod.
i still not sure what caused this but i noticed there are small debris inside the engine. so now i have new conrod installed but before i hit the track i would like to know how much shims do you guys run and what kind of plug. any suggestion will be highly appreciated.
Jeff