[s-cars] Stumbling at low rpm

[Vincent Frégeac]

Hi all,

My S6 developed a strange behaviour. It stumbles between 1500 and 2000
rpm but only in 2nd gear. In fact, it may have the same behaviour in
higher gear but the 2nd gear is the only one I go below 2K rpm. 1st gear
is correct whatever the rpm and 2nd gear and higher are correct passed
2K rpm. Stumbling is more pronounced under hard acceleration and also
disappears if I release the gas pedal and accelerate again. And last,
everything goes well when the engine is fully warmed up, after half an
hour or so. Idling is rock stable with some slight misses and I also
have a slight vibration at any rpm, only noticeable when you know the
car which used to be really smooth a few weeks before. BTW, no codes.

Recent work done: Generic O2 sensor, New F5DPOR, all under hood
electrical connections checked and cleaned. All this only lowered the
rpm where stumbling disappears from 2.8K rpm to 2K rpm.

Any idea?


Vincent

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