Nicht ein A4

So, I got my car back yesterday. Warrantied by AoA. No charge service. Cleaned. Overall a positive service experience.

By the dealer report, they removed the intake manifold, soaked it clean, manually cleaned the valves, and put it all back together.

The repair was done well. The underhood area is clean and neatly reassembled. The car feels more responsive and the exhaust note is slightly "crispier" than I recall. Admittedly, I have been driving a lovely A4 with ~200 less HP for the past 400 miles, but it still feels better than I recall. No more stumble and sputter on startup. Smooth even on cold start.

My only concern, which I shared with the SA, is that the cause of the carbon deposits was not identified. Everything seemed okay on testing and no parts were changed. I use the fuel they recommend. I plan wind it out a bit more and short shift less. It shifts smoother above 5K anyway. Not much else for me to do.

I am taking a wait-and-see approach. I plan to start using a fuel additive (as was noted on another thread). Drive the car and enjoy it.

Snow tires (second set of factory Ti wheels with Dunlop 3Ds) going on this weekend.

Nice to have it back.

audi_dtw

IMHO... using the right fuel as you have is the only thing you can do I think

daveak05

Glad it worked out well for you. GL.

silverRS4

I think fuel quality is their only explanation, but it doesn't make alot of sense. Tier 1 fuels have proper cleansing additives, but in the direct injection engines, the fuel is not sprayed directly onto the back of the valves anyway. My Service manager said that Audi told him that the European direct-injection engines had no problems with build-up. European fuel chemistry is different than American fuels so it must be somehow related to fuel, but I haven't heard of a correlation that makes sense.