I've had my 2008 2.0T into the dealer twice now for a subtle cycling or surging of the engine in certain situations and they seem stumped.

Here's whats happening...at very light throttle and low rpm the enging will pulse up and down 100 to 200 RPM. You can see the tach going up and down and hear the enging cycling up and down.

So far they have replaced the valve cover gasket saying that they discovered an internal air leak. That did nothing. Now they are saying that the vehicle is operating within specifications...meaning that it's not throwing any codes.

It's pretty obvious that there is something wrong and it's sometimes embarrasing when I have passengers in the car.

The only other symptom that I can say is that it seems to idle a bit rough...just a bit.

I'm under a CPO warrenty so I'd like to get it fixed. Any thoughts on what I can tell the dealer to look for?

Thanks for any help.

 

did they check the PCV?

 

Rough or goofy idle is one of the possible PCV valve symptoms.

 

Clean the snow pre-filter in the intake (pre-airfilter). And what everyone else said.

 

I just purchased the BSH PVC kit to see if it will help. Reading the sticky, it looks like a good $100 investment either way. I just hope I can install it without breaking anything!

 

Just take your time with the clips. It took me forever to get them off--especially the 4-sided one. Remove the plug on the HPFP (I think that's what it was plugged into--it's been a while) for a little extra room.

 

Some of these threads sometimes makes me embarrassed to say I work for a dealer.

Just because they're no codes doesn't mean there are no problems.

Vacuum leaks don't always throw codes.

But there are many things to look for. I would tell the dealer you want the shop foreman to look at it, because your getting really upset that it not being fixed correctly, and your thinking about calling Audi Of America to complain. It should light a fire under them to produce real results or it if is operating under normal conidition maybe you can get an intellegent reason why instead of getting the crap that sometimes comes out of the advisors mouth.

 

I replaced the PCV with the BSH kit without any issues and cleaned the snow filter thing but sadly it did nothing to resolve the issue.

Now for the good news....

I saw on another post talking about the same problem that a TSB has recently been released that describes my problem to a T.

I plan to call the dealer and have them check out this torque converter issue. Below is the TSB...


Technical Service Bulletin Transaction No.: 0
32 Shudder or RPM fluctuations while at cruising speed Release date: Feb 3, 2012

Condition

Customer may report shudder or RPM fluctuation while at cruising speed in 4th, 5th, or 6th gear.

Technical Background

Torque convertor clutches may have excess slippage while cruising.

Production Solution

Not applicable.

Service

1.
Check and verify that the software is at the highest level using TSB 2028053, 37 TCM software update for downshift concerns or 2028279, 37 Shift concerns when slowing vehicle. Also, check that the fluid level and condition is clean, full, and matches the required color per the applicable TSB.

Tip: If needed, update the software of the transmission and change the fluid before proceeding with this TSB.

2.
Test drive the vehicle to verify the concern is present.

If the concern can be duplicated, verify there are no fault codes stored for misfires and watch the Measure Value Blocks in the ECM to verify no misfires are seen when the condition is present.

3.
Check MVB 7 from the TCM. Verify Field 3 is reading control and record the slip count from Field 4 while the concern is present. The slippage of the TCC should not exceed 120 RPM in MVB 7 field 4 while the convertor is in control mode. The RPM surge should coincide with TCC slippage. If this reads higher than 120 RPM, the torque convertor should be replaced.

Tip: The TCC slippage will vary when in open TCC mode and should read 0 when in closed TCC mode, this is normal. Replace the convertor for high slippage when the TCC is in control mode (above 120 RPM) or for any slippage when in closed mode (MVB 7 field 4).

Tip: It is not necessary to receive a Repair Authorization to perform this TSB.

 

I would bet my life (almost) it is the torque converter clutch, more specifically the seals inside the converter for the TCC piston.

On a scanner, the MVB for TCC should show "OFF" and "ON" (or "open" and "closed"). If it reads "CNTRL" constantly, it is the converter. The ECM/TCM is commanding full TCC but not "seeing" it.

ANother good test is if it gets less noticable as the trans fluid temp gets to normal.

I've replaced 5 converters in '08 A4 2.0T's in the past couple weeks, and have 2 more on order. It's a tough one to diagnose unless you've seen it before. Then it's obvious what the problem is. First inclination is that it's an engine problem.

Now, if there was only a fix for the idle vibration on these cars.................................

 

Yeah there's a bunch of us that had our cars in for this surging, including mine, twice, while it was still under warranty. Dealer replaced N75, PCV, etc and that's it. Now the TSB comes out after warranty is expired... Dealer claims no responsibility. AOA needs to issue a warranty extension on the TC.