Problem with idle, A6 2,6 ABC. Please help!
 

Hi!

I have problem with the idle speed in my A6 2,6 ABC 1996, automatic transmission. The idle speed increases to 1300 rpm, alternative is varying between 800-1300.

Also problem with that the trottle is like a "on/off switch". I will try to explain below.
When i drive with constant speed and then lift the foot of the trottle and start to "enginebrake", it cuts the engine wery hard. When you start to increase the trottle it hits on the throttle very hard.


I have tried to clean the "idle valve" with no result. Also changed tre startingbattery without any difference. VAG-COM doesent find anything wrong.


There is one more thing that makes this even more difficult... I took off the battery for maby two hours and put it back without any difference. A moment later i did it again but only for maby five minutes and the car worked perfect! I drowe maby 30 km and everything was perfect. i stsrted and turned off the car several times without any problem. Then i shut off the car and let it cool down for maby one hour and the problem was back...

Please help me!

Pardon my bad english.

Kind regards, Juha, Sweden

I idle fluctuation could be many things, start simple and look for cracked, broken vacuum lines.

Since you have a vag-com, do a throttle body adaption. Also order a new throttle body gasket, remove your throttle body and clean out all the crap that has accumulated in there.

See Post 9: http://forums.audiworld.com/showthread.php?p=22371053

Also, I have linked to my personal MS OneNote note containing most of the useful info I have acquired over the years with how to's. Look at page 54 in the pdf and you will find a pretty good procedure to clean your throttle body.
http://cid-1c598fc7b134b0d9.office.l...ublic/Audi.pdf

Below is pasted from: http://www.ross-tech.com/vag-com/cars/throttlebody.html


Procedure for performing a Throttle Body Alignment on DBW Cars using KWP-1281:
(Check to see if the engine speaks KWP-1281 by looking in the top left of the Open Controller Screen Some examples of KWP-1281 engine controllers are 2000+ Golf/GTI/Jetta/New Beetle/Audit TT 1.8T)

Turn the key on but do not start the car.

[Select]
[01 - Engine]
[Measuring Blocks - 08]
Group 060
[Go!]
[Switch to basic settings]
Once you do this you will see the top right display say ADP RUN. The TB adaptation is being done as soon as you switch to basic settings. You will see the values change and hear the TB cycle for the first few seconds then it will stop. Leave it in Basic Settings for about 30 seconds.
[Switch to Meas. Blocks] button and you're all set.

Be sure not to touch the accelerator and make sure the engine is NOT running when you do this!

Any feedback on the solution to this problem? I have same issue and tried all the described suggestions.

Could it be the potentiometer? With vcds it only opens 79.4 when full throttle...

My '94 Audi A4 back in Germany did the fluctuation thing while idling and while driving. Was pretty interesting to drive it to the mechanic this way :D
Turns out all it needed was a new lambda sensor (also known as Oxygen sensor in the states).

While driving?
 

Did you have fluctuations while driving or did you have the hard cut on and off?

It was idling and driving this way (between 1000 and 2500rpm) without me ever touching the gas pedal. It was a manual so engaging the clutch was quiet rough some times.