Mikec6

Ok. I don't like throwing parts at the car without understanding the problem but I found a pretty decent price for a throttle body on ebay. It's from a 2004 a6 c5 2.7 turbo but apparently they're interchangeable with the 3.2 fsi c6. ..... We'll see. It should be here in a few days. I'll let ya's know what happens.

In the meantime. If anyone wants to see the symptom in action. I'll post a short video. It's starting the car, letting it idle for a few seconds and then slowly reving up to 1400 rpm until the bounce is evident. I tried to keep my foot perfectly stable in case your thinking it's my jimmy legs.

Mikec6

raj99

Let us know if the TB fixes it. Wish you luck and that surging does sound bad...sorry mate.

Mikec6

Sorry it took so long to get back to this. I ordered a TB off ebay and it came two days later , flap was seized, had to send me another one. Finally got it installed yesterday evening.

I was pretty confident this was going to solve it but after I did the TB adaptation procedure and started her up , all is the same😒. Fluctuation is still there at 1400 rpm in park. Seems to have a little vibration just before I get to that range as well. Other than that car runs great.

I guess I could live with it but I'd rather get to the bottom of it before it develops into something bigger. Any other ideas out there ???

Cam sensor? Vaccuum leak? Carbon buildup ? The fact that it's only at a certain rpm seems to iliminate those things as I would think it would be constant .

Mikec6

Thinking about doing a carbon cleaning. Great threads on how to do it . I'm no mechanic by any means but I think I can handle it. Before I take the plunge I'd like to cover my bases on doing the simple things.

I've done all the usual stuff like plugs and fuel filter, how about the PCv valve and egr valve, anyone check, clean those with success ?
The other thing I'd like to ask about is the highly controversial sea foam treatment , some swear by it some swear at it. Since I don't have MIL on , no codes and only a minor idle problem, do you think it's worth a try? Personally I think most additives are gimmicky and if takes dentist picks and Dremel bit to get that carbon off I don't see how a can of miracle juice would have that much of an effect.

On the other hand..... I keep reading of successful treatments. If there's no harm done I'm game. But if there's a danger in harming this beautiful beast.. I'm out.
Your thoughts.

KevinGary

As I said in an earlier post, I went down the same road and the problem was not corrected until I replaced the torque converter. Just bite the bullet and replace the torque converter.

Mikec6

I'm fairly certain this is NOT a torque converter problem as the issue is at idle in park. No surge in gear like so many of you are experiencing. Hope I never have to deal with that. 😒

am_ver

My issue was not entirely eliminated even after the TC was replaced (my car had the surge while going down a hill when the car was cold and no acceleration was applied). To this day, I can sense some degree of surge under certain circumstances. My gut tells me its an ECU bug.

audifsi3.2

When the engine is warm is like 3 cylinder work. Switch of engine and normal again. Car shaking when stay in neutral. Symptoms?

Mikec6

Symptoms are fairly constant. Hot or cold. Idle is stable and smooth in all other ranges except the range starting from 1200, it gets a vibration. The unstable fluctuation happens only when you try to hold the throttle at exactly 1400 rpm. Impossible to hold constant throttle at 1350 to 1450 rpm. Bounces 100 rpm in either direction. Hard to explain really.

In drive there is a small vibration as it accelerates through the 1400 rpm range. (Almost unnoticeable but clearly not normal). There is no surge like torque converter issues.

My suspicion is vacuume leak / clog or carbon deposits on valves.