P0300, P0304, P0306. Could feel a very mild rough engine at idle (cold or hot). Cleared the codes yesterday and started the car up again cold. They immediately came back. Swapped coil packs between cyl 4 and 1 and cyl 3 and 6 and did a cold start this AM. No codes. A little puzzled. Have driven it sparingly - just local - over the last week but did notice a cloud of light gray smoke when I floored it from a start. Going to do some highway runs to work this week and see if anything comes back. Have run Audi and Techron cleaner in the tank over the last six months and exhaust was clean.