Going Up Mountains

[Brian Pleet]

On my way across the Rockies, Vancouver to Calgary, my S6 suddenly started
to hesitate on uphill acceleration, making it difficult to pass anyone
going up a hill. The engine ran rough when accelerating, but smooth at
cruising speed. No signs of trouble in the car.

When I could finally pull the DTCs there were two:
00561 Mixture Adaptation 13-10 Adaptation Limit (Mul) not reached -
intermittent
00513 Engine speed sensor (G28) 27-10 Implausible Signal - intermittent

Now it's idling rough all the time, hesitating on acceleration.

Cause(s)?
dirty MAF - never been cleaned
spark plugs - 15k km on NKGs
engine speed sensor - original
ignition reference sensor - original
POS - changed one side, other is original

Thanks

Brian

95.5 S6 230k km
90 A90Q 235k km
02 TT Roadster 165k km