mcs

My A8 has had this little annoying fault for the last few months.

When doing between 35-60mph and lifting off the throttle to coast, the car will bounce the revs like the TC lockup is unlocking and locking. In all other ways the car drives fine.
There are no engine or transmission codes, I have removed and cleaned the throttle body (this was very clean to begin with) and unplugged the maf to check it was working - it is and the maf has been cleaned.

When unplugging the maf, the little vac operated door in the intake closed and opened again when i plugged it back in. I could hear it, and the vac operated intake arms are working normally.

Anyone have any ideas of what to check?

Mike

KevinGary

Since you have already done the throttle body, I am guessing the torque converter. That turned out to be the culprit on my old 2005 4.2. The problem started when the car had approximately 125k miles on the odometer.

2004A8L

How about in s mode?

mcs

It doesn't seem to be the torque converter. It locks up normally at other times and on the highway no problem.

My car has 139,000 miles on it.

I am thinking it could be a vacuum leak perhaps but I do not know the system well enough,

mcs

In S mode the lock up clutch performs perfectly. No bounce. This is why I think it’s engine and not gearbox