Dan,
I just had the same exact problem. The dealer did an intake valve cleaning (don’t recall the name, but it cleans off built up carbon from where they get sprayed with fuel). Then they said to replace plugs and coils (their estimat $550). So I did it myself using parts and videos from DeutchAutoParts.com for about $130.
Then when replaced, still had sputtering, and irregular idle. I found this 2nd problem, probably the original cause for the sputtering. A vacuum leak in the PCV valve. I bough the part from DAP for $40 and used their video to replace(very simple for my older FSI engine, 4 thin bolts). On my first test drive, the sputtering was gone and had additional, steady power, better than when I bought it used last year.
Just check out the Deutche Auto videos. I can send you a link to a doc they have to determine which engine type you have. Then the PCV valve part needs to match your engine type.
Let me know if you want to fix it yourself. You should first check if you are having vacuum leak codes. But it is a common problem, happens mostly around 50k miles, but could occur earlier.
Get the PCV Valve replaced before you spring big bucks for the plugs and coils ($130-150).
Hope this helps! My car has been running great for the past 3 weeks since I fixed it!
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