Phknlwyr

That gives me no comfort whatsoever, but I thank you for sharing. I now feel your pain.

I just visited the dealership to speak with the service tech and mechanic. The fuel injector cleaner made the problem much worse. They said at cold start this morning, the engine was a stuttering, misfiring mess. They identified 5 bad fuel injectors. They explained to me that the fuel injectors are aligned in two banks, one on each side of the motor. My bad injectors are on both sides so that they will have to remove both banks. Audi has authorized them to replace 5 out of the 10 injectors. This is inane given that there is no additional labor to replace all of the injectors since both banks must be removed to replace the obviously malfunctioning ones. The issue is that the injectors run $150.00 each. The guys at Rockville Audi are working to persuade the powers that be to authorize them to replace all ten under warranty. I might pay for it myself if they refuse. Stay tuned....

badziewo

I don't think that you have problem with fuel injectors.
From your log Saturday,21,May,2011,10:47:26:20260 the misfiring happen at cylinder 6 and 5 at the same RPM,time,speed.
Good luck

Phknlwyr

Thank you for your take on this. Other than believing that it is not an injector issue, do you have a theory about the problem with the engine? I'm at my wits end and am willing to try/recommend just about anything to the mechanic. Is there such thing as car acupuncture?

badziewo

Try this:
1 Throttle Body Alignment (TBA)
2 Catalytic converter test

Look at the CONVERTER CONVERSION VALUE.
If the value is more than 0.5 then catalytic converter is bad

Good luck

Phknlwyr

Thank you for this. Assuming the fuel injector replacements do not cure the problem, I will run these tests. I'm pretty certain they did the TBA last time they had the car and did the carbon cleaning. They specifically mentioned to me that the throttle would "re-learn" my driving style. The catalytic converter is a separate issue. I will run that test no matter what. Thank you again.

Phknlwyr

Just received word from my Audi service rep that all ten fuel injectors will be replaced under warranty. I should have the car back by Friday.

s4master1

It has catch my attention your ordeal,
I think you should change dealer before anything as it looks like they are guessing, and you giving suggestions don't help either.
at the end of my post will show you before and after pics of how valves look when properly cleaned.
If you looking for help here you are lost as two things are happening:
1. you not giving any numbers from the numerous sensors needed to run the engine, without this is impossible to make a test plan for your problem.
2. people here tell you try this try that out of no personal knowledge and just guessing or heard somewhere.

get rid of the obvious that makes no sense,
1 catalytics clogged up,
2 dirty injectors,
3 carbon build up.
none of these makes any sense as the car will run ok to 3500 and after 4500 correct?
so what's in between 3500 and 4500 rpm? two things one these engines have built in thru the ecm a feature that prevent them from going over 3500 rpm if there's no load to protect themselves, you can try to redline the engine while sitting and it won't let you
how does the ecm know engine load?, MAF sensor g/s readings, do you know your g/s readings?
we should start there,
the system is actually very simple thanks to computers,
it gathers data from sensors, we call them inputs
makes calculations based on that info, we call them processors = ECM x 2 in this case and send commands thru ground to numerous electrical/mechanical/hydraulic and pneumatic components that we call actuators.
so at this point all we need is to gather this data coming into the ecm/s and see the commands coming out.
one very important thing to consider is if any parameter has been changed (aftermarket chip/flash).
very important to see if you have cone air filters, this sit right next to the MAF sensors and can cause a whirlpool effect causing erratic readings in the air flow.
if you can get all this info I could put a test plan together for you and hopefully get your car finally fix.
since they actually listen to you ask therm to get a reading from channels 32 before they clear any faults.
also channels 1,2,3,4- 14,15,16,17,18-91,92,93
channel 125 while driving at 4000 rpm to see if any communication with the tcm unit is lost.

Phknlwyr

S4: thank you very much for your insights and advice. My car is bone stock: no chips, flashes, exhaust work, trick air filters etc.

I will reach out to the device tech today to discuss your thoughts.

Marco33

Phknlwyr; Nice posts, well written. Bummer to hear about this problem. Now I'm just a little hesitant to buy a higher mileage '07 S6, but the price depreciation is tempting. I recently saw an '07 S6 w/80k miles for $26,995 on the east coast (I'm in Denver). Perhaps I'll look at the '07 A6 4.2 but they might have that carbon issue with the FSI motor. I look forward to updates when you get it back.

Phknlwyr

Marco: thank you for your message. I think that my (recent) experience with my S6 is an aberration. I have owned the car for a little over two years and have been thrilled with its performance, reliability (especially as a daily driver), and utility - the trunk is huge, the rear seats accommodate my kids very well, etc. I would not shy away from a S6; rather, I would be selective with the one that I purchase. I would check service records and price the car according to what has/has not been done. For example, if it has not had a carbon cleaning, I would subtract $1200 or so from the price to budget for that expense. If the 55k service has not been done, that's a $780 bill. Brakes? Tires? You make your money (or in the case of cars, minimize your losses) on the buy. You will love a S6. Just exercise discretion when buying.