RPM's booging down and back up

[Tadas Blinda]

So got this 06 A4 and it has some 225+ miles on it. Has no CEL or any other warning lights on but it does this weird RPM drop and back when cold and it does the same but much less when warm.
Does anyone had this issue and knows what to look for to fix it?

https://www.youtube.com/watch?v=TMRFf1hGIRc

Here is the short video what it looks like, by the way it does not drop down if i hit the gas more, only at low speed.

Thanks for all the info in advance.

[80sGuy]

Could be a few things but I'd look into replacing both of these sensors:

Crankshaft Position Sensor (lower on the block adjacent to the Oil Filter Housing)
Camshaft Position Sensor (upper on the block)

Both sensors will emit the same symptoms. No harm in replacing them as they have a tendency to fail especially with this age and miles.

[KraZ4Riding]

^^ that. Just had very similar symptoms on 08 at around 150k miles. Generally car ran fine but would have these random drop outs/stutters under throttle. Had no misfires or other codes.

I suspect it was the crank sensor, but replaced crank and cam sensor within days of each other so I’ll never know. No more issues for several weeks now.

I did also clean the MAF with MAF cleaner.

[Tadas Blinda]

Gonna replace both of them and see if the issue still persist, and if it does, then will be looking for something else to replace.

[Tadas Blinda]

Replaced both sensors, cleaned air MAF sensor too and the issue is still there, just this time i have noticed it does happening below 2k rpm's and not happening above 2k rpm's.
Anything i should look in to next?

[Jayz691]

Replaced both sensors, cleaned air MAF sensor too and the issue is still there, just this time i have noticed it does happening below 2k rpm's and not happening above 2k rpm's.
Anything i should look in to next?

Auto Tiptronic? Looks like the common hunting issue..

Sent from my LM-V600 using Audizine Forum mobile app

[Tadas Blinda]

Would that mean it can be fixed or do i need to be looking for new transmission?

[Jayz691]

If its is the hunting issue, its the torque converter. Normally when cruising at light throttle, like on the highway, rpm will bounce 2-300rpm. Its a common issue with the tiptronic trans. Could try a fluid/filter service first, sometimes that helps(it improved mine).
Mine has been doing it for years...

Sent from my LM-V600 using Audizine Forum mobile app

[maleih]

Try the coolant temp sensor.

I would also suggest cleaning the throttle body.