piecewise

I have a 2006 Audi A4 2.0 T Quattro. Two days ago it had a 65,000 regular maintenance. They replaced an ignition coil (recalled part) and a faulty purge valve, which had been causing an evap leak. Systems were checked, Audi computer gave a green OK, all was well.

For three days.

On the third day, I started the car and it is shuttering now. It ignites to about 1,200 rpm, then settles down to just under 900 RPM. It shakes noticeably as if it's about to stall (but never does).

Changing gears does nothing. Accelerating fixes the problem (it's only at idle).

Turning ON the A/C seems to lessen the problem, though it's still noticeable. Turning OFF the A/C makes it very noticeable.

Any ideas?

piecewise

Note: there are no indicator lights on and it drives well otherwise.

sws_audi

I having the same problem with my A4 2.0T but my car is throwing codes:

-System too Lean at idle
(P2187 -004- No Signal/Communication -MIL ON)
-Leak in Air Intake System
(P2279 -002- Lower Limit Exceeded -MIL ON)
-Idle Control System RPM: Higher than Expected
(P0507 -001- Upper Limit Exceeded -MIL ON)

I took it into the dealer and they replaced the throttle body but it did not fix the problem. The codes came back.

It seems to do a cycle. If I rev up the engine to 2500 rpm and then let it idle it will drop to 1000 rpm then go to 1200 rpm then drop to 880 rpm and idle rough. If I let it idle for a min or two it will start to idle normally.

I cleaned the mass air flow today and cleared the codes and that seemed to help but not fix the problem.

mscav

Mine had the same codes and behavior, it was the PCV valve. (They call it something slightly different, like crankcase breather, but it's the same thing). I replaced it and it idles very smooth at a normal RPM.

sws_audi

So I went and changed out the crankcase breather valve. Now it is idling perfect. Thanks!

The Traveler

PCV: Positive Crankcase Ventilation.

pgthe1

My first post
Anyway, I just bought an 2006 a4 s line 2 weeks ago. I too had the wierd idle issue. After looking on the boards here, i found this thread... i went down to the dealer picked up a new PVC... installed it just now and the problem is gone. They also replaced my coil packs under the re-call.

audimayne16

Audi a4 b7 2.0 quattro 117k miles

Anyone know how to tune the idle sound without expensive cost? Hearing puttering in my idle more than i like. I added new performance hoses. What else can i do?